BISATELLITED DERIVATIVES OF CW 15: CY'IKXSENEI‘IC AND CLINICAL STUDIES Lawrence Wisniewski A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DCII‘IOR OF PHIIDSOPHY Department of Zoology 1978 PLEASE NOTE: Some pages tend to wrinkle because of the glue used for mounted illustrations. Filmed as received. UNIVERSITY MICROFILMS INTERNATIONAL ABSTRACT BISATEILITED DERIVATIVES OF CHRQ‘DSCME 15: CY'lmENETIC AND CLINICAL STUDIES By Lawrence Wisniewski Extra de novo bisatellited chronosomes in five unrelated patients were identified as inv dup (15) (pter -—- ql:pl or ql .. pter) by QFQ, GTG, RHG, and anti-S-methylcytidine banding. Clinical studies on these patients, and 12 probable and 7 confirmed cases in the literature, indicated an association between inv dup(15) and a mildly dysmorphic syndrome. Features present in virtually all cases included mental and developmental retardation, hypotonia , and behavioral disturbances . 60% - 80% had strabismus, short stature, seizures, and nonspecific dermatoglyphic abnormalities. 20% ~ 60% had mild facial and limb dysn'orphisms, and vertebral anomalies. Parental ages were distinctly elevated. Inv dup(15) is likely to have arisen via the meiotic mechanism of translocation , U-type exchange , or parental paracentric inversion heterozygosity. Proximal and distal QFQ polymorphism asymretry in all five patients ruled out an origin via sister chranatid exchange . An analysis of the theoretical segregation behavior of the derivative suggested the occurrence of second division nondisjunction in four of our cases and one in the literature. A sixth patient with an extra bisatellited chrcmosome was also evaluated. The error in this case was tentatively identified as t(lS;15) (pllqu4) . The phenotypic findings were similar to those of inv (111;) (15) . ii TABLE OF QDNTENTS Introduction . . . . . ..................... Literature Review ....................... 1a. lb. Small supernumerary chromosomes in man ........ Small supernumeraries derived from D and G group chronosomesotherthanchrarosorrels. . . . . . . . . 1c . Small supernumeraries not derived from acrocentric automs. O O O O O O O C O O O O O O O O O O O O O O ld. Population studies on supernumerary chromosomes . . . 2a. Supernumerary chromosomes derived from chronosome 15 . 2b. Patients with proximal trisomy 15 .......... 2c. Bisatellited derivatives of chronosome 15 in category 3 . . . . ................ 2d. Comparison of features in categories 1 and 2 with thoseincategoryB........ ...... 3a. Dicentric chronosomes inman . . . . . . . ..... . 3b. Functionally dioentric chrarosomes (type 1) . . . . . 3c. Functionally nonocentric dicentrics (type 2) . . . . . 3d. Evidence suggesting a type 2 structure for inv dup (15) chronosonesw. ..... ...... 4a. Cytological mechanisms related to inv dup(15) ..... Materials and Methods ....... . . . ........... 1. Ascertainment .................... . 2. Clinical evaluation . . ................ 3. Cytogenetics . . ................... Results . . . . .................... . . . . 1.Casereports............ ........ . 2. Summary of phenotypic findings .......... . . 3. Linkage data . . . . .......... . ..... . 4a. C‘ytogenetics of cases I-V ...... . . . . . . . . . 4b. Cytogenetics, case VI . . . ...... . ....... Discussion.. ........... ...... 1a. Identification of the bisatellited chrcnosomes . . . . lb. Further characterization of the inv dup(15) 15 15 17 20 20 23 23 24 24 27 27 45 45 59 61 61 63 iii 2a. The inv dup(15) phenotype, cases I-V ......... 66 2b. The inv dup(15) syndrome . . ............ . 68 2c. Unresolved cases similar to the inv dup(15) . ..... 75 2d. Carparison of proximal trisomy 15 with the inv dup(15) syndrome ..... 76 3a. Mechanisms in the origin of inv dup(15) ........ 78 3b. Additional etiological considerations ........ 84 3c.Etiologicalconclusions................85 Summary ............................. 85 Appendices Appendix A - Case Surmaries of Previously Reported Cases . . 88 Appendix B - Phenctypic Checklist Supplied to Previous Investigators ................... 104 Appendix C v Analysis of Familial Polynorphisms, Cases I-V ...... . . . . . ........... . . . 108 List of References ...................... 112 Table Table Table Table Table Table Table Table Table Table Table Table Table Table 10 ll 12 13 14 iv LIST OFTABLES Phenotypic findings in 14 patients with proximal trisomy 15 .......... . . . . . . ...... 8 Cytogenetic findings in 19 cases with presumed or confirmedinvdup(15) ........ .13 Phenotypic findings in 16 cases of presumed or confirmed inv dup(15) ................. 14 A comparison of phenotypic findings in patients from Tablesland3... ...... . ..... .....16 Phenotypic findings in cases I-V . . . ........ 46 Linkage data ..................... 47 Normal acrocentrics not excluded as contributors in cases I~III ...................... 53 Normal acrocentrics not excluded as contributors in cases IV and V .......... . . . . ...... 53 Possible rearrangements giving rise to supernumeraries as determined from Tables VI and VII . . . ...... 57 The highest level of nosaicisn excluded in patients with .95 and .99 confidence levels . ..... . . . . 58 Possible rearrangements giving rise to the super- numerary in case VI as determined by familial polya- norphisms . . ..... . ..... . ......... 58 Phenotypic findings of inv dup(15) syrflrcme in pre- viouslyreportedcases .. ...... ........69 Comparison of findings in previously reported cases withtlnseincasesIv-V ....... .. 72 Ocuparison of phenotypic findings associated with proximal trisomy 15 and those in inv dup(15) syndrome . 77 Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 10 11 12 13 14 15 16 17 LIST OF FIGURES Case I] DD 0 O O O O O O O I O O O O O O O O O O O 0 Case II, CL ........... . ......... Case III, ML ...... . . . . . ........ . CaseIV,RF........... .......... Case V, BL ..................... Case VI, TM . ............. . ..... Conventional giemsa staining . 'Ibp: normal D and G group autosomes. Bottom: inv dup (15) from ca%s I‘v O 0000000000000 O O O O O O O Inv dup(15) in satellite association ........ QFQ staining. Top: normal D and G group autosomes. Bottam: inv dup(15) from cases Iv-V . . ....... GIG staining. 'Ibp: normal D and G group autosomes. Bottom: inv dup(15) frcmcases Io-V . . . . . . . . . RHG staining. Top: normal D and G group autosomes. Bottom: invdup(15) fromcasesIv-V. . . . . . . . . CBG staining. 'Ibp: normal D and G group autosomes. Bottcm: inv dup(15) from cases Io-V ..... '. . . . QFQ polymorphisms in family of DD. Top: paternal. Middle: maternal. Bottcxn: DD...... QFQ - CBG polymorphisms in family of CL. Upper photo, QFQ. Top: paternal. Middle: maternal. Bottom: CL. Imer photo: same chromosates with QFQ polymorphisms in family of ML. Top: paternal. Middle: maternal. Bottom: ML........... QFonlymorphismsincasesIVandV. 'Iop: RF. Bottcm:EL ..... ....... ..... QFQ polymorphisms in family of 'IM. 'Ibp: paternal. Middle: maternal. Bottom:'1M........... 28 31 34 37 40 43 49 49 49 50 50 50 54 54 55 55 55 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 vi Extra chromosomes in case VI shown with a normal G group for size comparison. Top: conventional giemsa. Bottom: RHG staining. . . . . . . ..... 60 Alternative structures for inv dup(15) ....... 64 Five mechanisms in the origin of inv dup(15) . . . . 79 First division nondisjunction and second division centrcmeric deactivation of inv dup (15) derived from either a paracentric inversion, or a U-type exchange............. ........ .81 First division centroreric deactivation and second division nondisjunction of inv dup(15) derived from either a paracentric inversion or a Ua-type exchange . 82 INTRODUCTION The delineation of syndromes associated with mildly dysmorphic autosomal errors is a relatively difficult process. Nany affected patients lack compelling indications for chromosome analysis , and are overlooked. In other instances , technical limitations hamper interpretation and comparison of cytological data . These problems are evident in previous studies of bisatellited chromosomes believed to represent errors of chromosome 15. The cytological nature of these derivatives, and the associated pheno- type, are not well understood. This paper attempts to clarify some of the characteriStics of this disorder. Six patients with mental retardation and minimal phenotypic findings were evaluated over a two year period. Each had a small acrocentric bisatellited supernumerary , with banding chracteristics similar to the proximal portion of chrotosome 15 . The clinical findings in these patients suggested an association between the bisatellited chromosomes and a mildly dysmorphic syndrome. Data supporting the delineation of this syndrome, and data bearing upon the identity, origin, and structure of the extra chromosomes, are reported here. Literature Review la. Small supernumerary chromosomes in man. Prior to 1970 , cy‘togenetic techniques lacked the resolution necessary for precise identification of most markerl, chromosomes. Small supernumeraries were particularly troublesome, in that they resembled many normal chromosores or their derivatives , but were not associated with consistent phenotypes. Small supernumeraries of a de novo origin were usually accompanied by mental retardation and congenital anomalies; familial supernumeraries frequently occurred in phenotypically normal persons, and could not be related to clinical disorders . Phenotype-karyotvpe correlations eventually led to recog- nition of the XYY male (Sandberg et al., 1961) , and the Cat-Eye syndrore (Schachenmann et al., 1965) . Attempts to define full trisomy 22 (Hsu et a1. , 1971) and a "metacentric microchrcmosome" syndrome (Abbc and Zellweger, 1970) , were less successful. Partial D group trisomies were occasionally suggested by certain soratic characteristics (Yunis and Hook, 1966) , or translocation carrier parents (Bloom and Gerald, 1968) . The introduction of chromosore banding techniques in the early 1970's transformed the study of supernumerary chrotosomes. A number of abnormalities were subsequently associated with specific pheno- types, and more data bearing on the origin of small supernumeraries lBy convention, unidentified chrotosores are frequently referred to as "markers" (Chicago Conference, 1966). became available. These observations are reviewed below. lb. Small supernumeraries derived from D and G group chrorosores other than chrorosore 15. Proximal trisomy 13 has been encountered in a limited number of cases, and is associated with low birth weight, microcephaly, small mouth, bulbous nose, micrognathia, ear deformities, clinodactyly, increased neutrophil projections, and mental retardation (Schinzel et al., 1976, Wilroy et al., 1977) . Proximal trisomy 14 is associated with a pattern of malformations that includes mental retardation, prominent nose , broad nasal bridge , hypotelorism, palate anoralies, long upper lip, poorly defined philtrum, characteristically shaped mouth, short neck, limb anomalies, and short stature (Simpson and Zellweger, 1977, de Grouchy and Turleu, 1977) . Proximal trisomy 21 is associated with mental retardation and few soratic amoralies (Williams et al., 1975, Hagomeijer and Suit, 1977) . Studies on distal trisomy 21 have mapped the segment responsi- ble for the Down syndrome pherotype to bands 21q21~22 (Aula et al., 1973, Williams et al., 1975, Wahrman et al., 1976, and Hagoreijer and Suit, 1977) . Proximal trisomy 22 is associated with mental retardation, anti:- mongoloid slant , preauricular tags and sinuses , large or lowset ears , congenital heart disease, and minor skeletal anomalies (Garlinger et al., 1977) . Full trisomy 22 is associated with a syndrome of microcephaly, asymmetrical cranium, flat occiput, strabismus , epicanthus , short beaked rose, ear deformities, long upper lip, long philtrum, cleft or high arched palate, micrognathia, preauricular tags and sinuses, dislocated hips, tapered fingers, hypoplastic male genitalia, con— genital heart disease, mental and growth retardation, and hypotonia (de Grouchy and Turleau, 1977) . Hsu and Hirschhorn (1977) also noted an antimongoloid slant and hypertelorism. The marker chrotosore associated with the Cat-Eye syndrore was recently identified as a bisatellited derivative of chromsome 22, with proximal and distal C bands. Phenotypic findings common to these cases include coloboxa , micrognathia , depressed nasal bridge, hyperv- telorism, preauricular tags and sinuses, congenital heart disease, renal anoralies, anal stenosis and atresia, and mental retardation ('Iborey et al., 1977). lo. Small supernumeraries not derived from acrocentric autosores. Normal males with additional apparent deleted Y chrotosores have been reported by Nielsen et a1. (1971) , and Christensen and Nielsen (1971) . Wisniewski and Higgins (1977) described a mentally retarded boy with multiple anomalies and an extra deleted Y as the result of nondisj unction following a de novo Y/autosome translocation. 3 to l meiotic disjunctions in carriers of balanced autosomal transloca’ tions have produced a number of probands with various 47 + marker karyotypes (Lindenbaum and Bobrow, 1975) . 18p isochromosores repre- sent still another form of small marker (Ogata et al., 1977, Tangheroni et al., 1973, Nielsen et al., 1974, Taylor et al., 1975, Balicek et al., 1976) . Condron et al. (1974) described psychomtor retardation, small head, lowset ears, small mouth, narrow high arched palate. frail habitus, and upper motor neuron lesions as features associated with this syndrore. Paluthke et a1. (1976) identified a small meta- centric marker as an extra deleted number 17. A few rare cases of centric fission in man have also been described (Archidiacono et a1. , 1978, Sinha et al., 1972, Hansen, 1975, Dallopiccola et al., 1976). In some cases, the morphological characteristics of small metacentric supernumeraries led investigators to conclude that they were fused acrocentric short arms, the products of balanced reciw procal Robertsonian translocations (Palmer et a1. , 1969, Friedrich and Nielsen, 1974). Family and newborn studies have suggested that these presumptive t(p;p) chronosores function as benign familial traits (Friedrich and Nielsen, 1974, Palmer et al., 1969, Soudek et a1. , 1973) . C banding has been applied to estimate the heterochroratic content of sore unidentified small chromosomes. Souiek and Sroka (1977) found that small markers varied in their C banding properties. Some were entirely heterochrcmatic, and presumably benign, while others possessed variable amounts of nonstaining euchrotatin. The presence of more than one C band was noted in sore patients, along with a bisatellited appearance (Soudek and Sroka, 1977 , de Gutierrez et a1. , 1975) . ld. Population studies on supernumerary chrorosores. The incidence of supernumeraries in newborns and institutional popualations has been estimated by a number of investigators . Pooling the newborn sttfiies, Jacobs (1974) placed the frequency of unidenti- fied supernumeraries at .02%. Friedrich and Nielsen (1974) reported an incidence of .6 per 1000 liveborn, and Gerald and Walzer (1970) reported an incidence of .8 per 1000. As expected, studies on re— tarded populations gave higher frequencies. Jacobs et a1. (1972) reported a frequency of .28% in a mentally retarded group. Speed et a1. (1976) found .32% in a complete survey of the mentally re- tarded in Northeast Scotland. 2a. Supernumerary chrorosores derived from chromosore 15. According to Iauritsen (1977) , full trisomy 15 occurs in 5% of all karyotypically abnormal spontaneous abortions. In contrast, a liveborn with full trisomy 15 has never been described. Partial trisonies have been observed in living individuals, and those related to this report fall into three morphological categories: 1) de novo presumed proximal trisomy 15 without confirming evidence, 2) proximal trisomy 15 confirmed through a balanced carrier parent, 3) de novo bisatellited acrocentrics believed to represent either proximal trisomy or tetrasory of chrorosore 15. The term proximal refers to portions of chrorosome 15 bordered by lSpter and the landmark band, 15q21. This includes the short arm and approximately one half of the long arm. The short arm of chromo- some 15 is believed heterochroratic, and is not known to contain genetic material necessary for normal developrent. Excess long arm euchromatin is presumed the cause of clinical defects in these patients. Specific syndromes associated with trese errors are poorly defined. Earlier attempts to delineate them made use of patients in all three categories without regard for cytogenetic heterogeneity (Centenall and tbrris, 1975, Castel et al., 1976) . The results were confusing and equivocal . The following review covers patients in categories 1 and 2 separately from those in category 3. (Case sum- maries for all patients in these categories are appended. The cases are numbered according to their appearance in the appendix.) 2b. Patients with proximal trisomy 15. Fourteen previous cases with proximal trisomy 15 fit categories 1 and 2. Phenotypic findings present in at least three of the 14 patients are summarized in Table 1 . Mental retardation was the only uniform finding. More than half the patients had strabismus, micro- gnathia, arched or cleft palate, and abnormal dermatoglyphics. Approximately half also had lowset malformed ears, growth retardation, and genital anomalies (males). Heterogeneity was evident; half of the patients were trisomic for 15pter -) q15 or less, and the other half for 15pter ~9 q21-22. The latter group did not have unique findings associated with bands q21v-22 , with the possible exception of hyperactivityz, and appeared less malformed than the pter ..., q15 trisomies. Malsegregating familial translocations are considered a less reliable source of 2Hyperactive patients occur in category 1; it is interesting to compare their histories (see Appendix) with those of the inv dup(15) cases (Table III). Cases 1, 2, and 4 resetble the inv dup(15) patients. Case 3 does not, and is the only one with cytogenetic evi- dence firmly excluding it from the inv dup(15) category (C banding). The other three may have modified inv dup(15) chrorosotes, and this point is covered later in the discussion. HH\~ ma\ma «H\e ¢H\m mmHME m\m 4H\v Ha\m HH\¢ HH\m m\a «axe HH\m aaxma HH\e HH\¢ aa\m «H\m oa\e HH\m Haxm HH\m zo\mm + + l I I I I . <1 <1 l+++l +1 I l I I + + .. + + + + + H H I H 1+. + + + + I + + .. + .. + + .. i + i .. .. + + .. .. .. i + i I. .. n + + + + L n .. ... .. ... I + .. .. + + i i i + + + .. .. + + i .. + ... + + + + .. + ... + + i ... .. ... n + + a. o a. .4 o a o o (a. a + + .. + + + + In. In In I. I... + Ir I. It II + + .. .. i l + + + + .. + + + .. .. .. .. + .. n + + .. .. + .. I + + .. .. + .. i + + v.m H.N o.m m.N v.N w.N Hm VH m ma m Hm NH m va 2 ..m S E m .m 2 2 2 .m m m w I I m o o 0 O n n n m m w m m m m m m h OH m NH «a ma m m «.mH ssomnuu Hmeaxoua apes mucmaumd «a an mmcaecau unasuocmam moflnoioonmfimo coaumonmumm Hanan: coflgoumumm 538w managed»: be H2582 Become m a m mace endgame sasuomeocnao mwmonomx banana ummfiu mama 850mg mama ummsoq x82 flaw 33mm capo mcaamomm 83300032 mcfifiofldm masmnnmuum pagoda: manomexwxam omocmupm no? moan—mm Hmso A. 9: unoemz gm mom xmm H95 3031.62 mammauu amapnmm * mmmu ..n manna. A boomumo fi 923 a 93 .m .m ..H mommu .nouum on» 5 ”Edmond ma 9.808050 mo mug gmmouofiu m0 .830 5 cognac mum mommu « #20 u o e88... n a m. Hobo: anemone—e n m 83ch 3835 u m Snag acumen u e HBNNHUHN 595: u 0 «we 8. do I ~8an u a fly 8. 2w T Emma u m . Boise H 3..an 10 data for syndrome delineation, because a complicating abnormality involving a second chrotoscme is usually present. Familial translo- cations were responsible in five of the seven 15pter ~+ qlS cases, and three of the seven 15pter --) q21~22 cases. This alone may account for the impression that 15pter --) q15 trisomies are more damaging. 2c. Bisatellited derivatives of chromosote 15 in category 3. Bisatellited chromsores known to represent errors of chrorosome 15 have very distinctive characteristics (Schreck et a1. , 1977, Van Dyke et al., 1977) . 1) They are approximately the same size as 15pter ~+ q21-22, and have G and Q banding patterns matching this area. 2) The G technique produces a distinctive dark band on the marker coinciding inposition with the chromosote 15 landmark band 15q21 (see Figure 10). later studies revealed that this band was not 15q21, but corposed of C band positive heterochromatin (Schreck et al., 1977, Van Dyke et al., 1977, Pfieffer and Kessel, 1976) . 3) A definitive characteristic was demonstrated by Schreck et al . (1977) using a technique originally described by Miller et a1. (1974) . Miller et a1 . demonstrated the preferential binding of antibodies against the nucleotide 5—methy1cytidine by indirect immmoflmrescence following slide exposure to ultraviolet irradiation . The areas of handing were confined to the heterochrolatic regions of chromosotes 1, 9, 15, 16, and mid Yq, giving a powerful technique for differ- entiating chrotosore 15 abnormalities from those involving other acro- centrics. The technique was first used to cmfinm chrorosore 15 translocations in two families (Breg et a1. , 1974) . later, Schreck 11 et a1. (1977) applied it to a number of patients with extra G like chromsores. Among these cases were three with bisatellited chroro- scmes previously interpreted as chroroscme 15 derivatives (Breg et a1 . , 1971, Parker and Alfi, 1972, Bucher et al., 19733). Anti-S-methylcy~ tidine banding demonstrated two intensely staining areas corresponding to the proximal and distal C bands on these markers. The results clearly revealed that the bisatellited chromosores were corposed of a small segment of euchroratin bordered on either end by material derived from the short arms of number 15. The euchroratin presumably represents either trisory or tetrasomy of proximal 15q. Schreck et al. described the rearrangement as inv dup(15) (pter ~> q1:pl or ql at pter) . (This designation is adapted for the remainder of this report.) Previous reports of chrorosores with characteristics like those above were located in the literature. Seven cases of inv dup(15) confirmed by anti—S—methylcytidine banding were available (Schreck et al., 1977, Van Dyke et al., 1977) . These were compared to 15 other patients with bisatellited supernumerary acrocentrics of G group size or slightly larger. Twelve of the unconfirmed cases had 1) G and/or Q patterns identical to 15pter --) q21, or 2) a distal G band resembling 15q21 that was C band positive. These 12 cases were considered as probable inv dup(15) . A summary of the cytogenetic data on the 12 probable and 7 confirmed examples is given in Table 3The case briefly described by Breg et a1. (1971) is one of the two patients described by Crandall et a1. (1973) . 12 2 .4 Original studies suggested or, in one case, confirmed with polymorphisms, a chrorosore 15 origin in all but three of the probable cases. Rasmussen et a1. (1976) and Kakati and Sinta (1973) interpreted chrorosome 13 as the origin in their reports due to similarities in C band polymorphisms.5 he questioned this evaluation, and felt that other cytogenetic data presented favored a chrorosore 15 origin. Jacobs et a1. (1978) made no attempt to identify the marker in their patient, but presented G banded material consistent with 15pter «a q21. All total, 19 cases were considered confirmed or probable examples of inv dup(15) . Phenotypic findings in 16 of the 19 are summarized in Table 3.6 mental retardation, varying from profound to mild, was present in all cases. Comon features included strabismus, abnormal dermatoglyphics , hypotonia , developmental and growth retardation . Seizures were present in eight cases, hyperactivity in four, and autism in three. Extensive physical malformations were generally 4The three remaining patients with bisatellited supernumerary acrocentrics are briefly described here. The first case was reported by Unis and Book (1966) . The patient was a seven year old male with severe mental retardation, a convulsive disorder, but no other major malformations . Autoradiography suggested that the extra chrotosore was derived from a number 13. This diagrosis was supported by the demonstration of increased neutrophil projections, a claracteristic of full trisomy 13. The next case was described as an example of Rubinsteinv-Taybi syndrore by Padfield et a1. (1968) , and was evaluated by Simpson (1973) . Simpson identified a supernumerary bisatellited chromosore, and considered it a deleted 14 with G banding. This case is again mentioned in the discussion. The last patient, a child with Cat Eye syndrore, has been previously discussed (Tbomey et a1. , 1977) . 5In both of these reports, it was suggested that chrotosote 13 usually had the largest C bands in the D group. This is contradictory to our experience; chrorosore 15 C bands are usually the largest, and chrorosome 13, the smallest, with our Q to C method. 5Case 24 (Speed et al., 1976) was not included because no clinical data had been published with the report. Case 26 (Power at al., 1977) was a pherotypically rormal female mosaic. Case 33 (Jacobs et al., 1978) had to be excluded because of septic meningitis at age 1. 13 Table 2. Cytogenetic findings in 19 cases with presumed or confirmed inv dup(15) . Case# Satellites on pandq Satellites on q only Q bands = 15pter --q21 G bands = 15pter ~—q2l Cbandson pandq Anti-5*- methylcytodine A QandC polymorphisms = chrom. 15 + + 15 16 19 + 17 18 20 21 22 23 25 27 28 29 30 31 32 26 24 33 +++ +++++ +++++ +++++ ++ + + + + +++++ ++ +++ + + ++ 14 m m\m v m mafia m\m m\m oa\m m\~ m\o Cm m\m m}. mm vm vH\oa + m\m said a Nm Ne mm 2 Hm mv ms 2 om mm 5N mm mm om Ne mm pm om mm mm om mv mm vm mm + + + + + + + + + + + + + + ... + + + + + + + + + + + + + + + + + ... + l i + + + + + + .. + + + + + + + + + + + .. + .. + + + .. + + .. .. + II I: I. I. I... + .l. + I: + + ... I. .. .. + + + + + .. + + ... + + .. + i .. I .. m.m o.m N.m m.N w.m v.m m.N N.m 2 m .m S rm 2 m 2 2 2 m. h «M NH m om a Ha HA m.H mm mm mm mm Hm om ma ma ha N N . Amdocp NEH Emcee so oofifimuo mo woman ma 5 mofipfim UHSQEAE MN I I + I + 0H ma mm mm ma mos Eco mod encumber wow Hassocns madam Eggnog? 5.35 8383mm 3cm: coumpnmumm fig . 85mm 38.5398 goo»: mmpe mfiflms mogagmfimo memofioom 33mm owned mgcmoaom mamanmuum mango“: 79: became fihm xom mad t mmmu .m manna 15 absent. A very provocative elevation in mean parental ages was evident . 2d. Corparison of features in categories 1 and 2 with those in category 3. Although the published data are incorplete, certain differentiating trends are suggested in the comparison of phenotypic findings of categories 1 and 2 with category 3 (Table 4). In general, physical malformations were more comon in the partial trisomies. Micrognathia, severe palate anoralies, and ear abnormalities were most frequent in categories 1 and 2, while convulsive disorders and behavioral aberrations appeared to characterize the inv dup (15) patients. The incidence of strabismus , epicanthus , dermatoglyphic errors , growth and mental retardation were relatively similar in both. 3a. Dicentric chromosores in man. Recent studies have suggested that two centroteres may be included in the structure of inv dup(15) chrotosores (Schreck et al., 1977, Van Dyke et al., 1977). Two types of dioentric chrorosores are krown to occur in man. Type 1 is functionally dioentric, and forms two primary constrictions prior to anaphase . Type 2 has only a single functioning centromere . It forms a single primary constriction prior to araphase, and is initially indistinguishable from a normal monocentric chromosole . 3b. Functionally dioentric chrorosores (type 1) . Type 1 dicentrics are associated with chrorosore breakage 16 Table 4. A corparison of pherotypic findings in patients from Tables 1 and 3. Partial Trisomy Strabismus 8/14 Micrognathia 6/11 Epicanthus 3/14 Palate Anomaly 12/14 lowset Fars 7/14 Malformed Ears 4/9 Abnormal Dermatoglyphics 7/11 Hypotonia 5/14 Mental Retardation 13/13 Growth Retardation 6/14 Hyperactivity 3* Seizures 0 Autism 0 Presumed inv dup (15) 10/14 0 4/9 2/6 1/7 6/9 9/10 15/15 5/9 4* 8/9 3* * Positive findings only for these features were scored, since nega- tive findings were difficult to determine from the published descriptions . 17 syndrores (German, 1972), induced chromosome damage (Bloom, 1972), and fibroblast senescence (Benn, 1976) . Inherited type 1 dicentrics have been rarely observed. Jacobs et a1. (1972) described only a single type 1 dioentric out of 24,000 individuals karyotyped for various reasons, and Hamerton et a1. (1975) did rot observe any in 46,000 newborns. 16 patients with problems of sexual differentiation and type 1 dioentric Y chrotosomes were reviewed by Cohen et a1. (1973) . The rarity of inherited type 1 dicentrics can be attributed to their instability over many generations . Since both centromeres remain functional , an opposing orientation on the spindle apparatus eventually occurs. This results in breakage or corplete loss of the dioentric due to anaphase bridging (Father and Stone, 1933, ENans, 1962) . In corn, anaphase bridging may result in the classic bridge— breakagev-fusion cycle of McClintock (1951) . Evidence for a similar process in man was reported by Van Dyke et a1. (1977) . Exceptionally stable type 1 dicentrics have been reported (Sears and Camera, 1952, Niebuhr, 1972, Cohen et al., 1973, Hair, 1953, in Warburton et al., 1973) . Nielwhr (1972) , Cohen et a1. (1973) , and Hair (Warburton et al., 1973) suggested that the stability of these rearrangements might be due to the closeness of their two centro— meres . 3c. Functionally morocentric dicentrics (type 2). Sears and Camera (1952) proposed tlat the inactivation of one centrorere of a dioentric could produce stability. Centromeric deactivation results from functional dominance of one centrotere over 18 the other; the weaker centrorere retains its ability to orient on the spindle, but can do so only in the absence of the dominant centro- mere. This theory is currently accepted as an explanation for type 2 dicentrics in man. Type 2 dicentrics initially appear morocentric . All centroreres in the huran karyotype are marked by adjacent C banding heterochrota- tin, and an inactive centromere is suggested when C banding material occurs at a position expected for a second centrorere as determined by other banding techniques. Further examination of the area in question usually reveals additional morptological data consistent with this assumption. Inactive centroreres were first described on X chrorosore derivatives (Disteche et a1. , 1972) , Robertscnian translocations (Niebuhr, 1972) , and autosotal translocations (Warburton et a1. , 1973) . Since these reports, many other cases involving X chrorosomes (Valenta et al., 1977) , and fewer cases involving autosotes, have been described (Soudek and Sroka, 1977, Van Dyke et al., 1977, Roberts et al., 1977, Nakagote et al., 1976, Schreck et al., 1977, Pallister et al., 1974, Wisniewski et a1. , 1978) . Characteristics cormon to most type 2 dicentrics are: 1) A minority of cells usually have sore structural peculiarity localized near the deactivated centromere. This included a tendency for the chroratids to oppose each other in a semi-constricted manner, to form constrictions-like rotches , or to overlap suggestively (Pallister et al., 1974, Disteche et al., 1972, NakagoIe et a1. , 1976, Wisliewski et al., 1978) . Unusual modifications of the l9 condensation process in distal regions of these rearrangements were mentioned by Wisniewski et a1. (1978) and Pallister et a1. (1974). 2) Centromeric deactivation may be incomplete in some cells. Type 2 chromosomes with two primary constrictions were noted by Niebuhr (1972), Therman et a1. (1974), warburtcn et a1. (1973), Pallister et a1. (1974) and Wisniewski et a1. (1978). In general, the frequency of true dicentrics was only a few percent, and.scme observers failed to note any (Disteche et al., 1972, Nakagore et al., 1976) . Mosaicism in many cases of type 2 isodicentric X chromosomes can be explained by the loss of the chromosome in some cells early in development (Valenta et al., 1977). Technical difficulties generally limit the study of human mitosis, but Therman et a1. (1974) produced photographs showing anaphase lag or bridging in a case of a type 2 isodicentric X. A mosaicism suggestive of a bridge—breakage~fusion cycle was described by van Dyke et a1. (1977). 3) The relative activity of both centromeres can be estimated ifixmithezmcrphclogy and banding of asymmetrical type 2 rearrangements. In cases where this was possible, a specific centromere was always seen to dominate the other, a relationShip that apparently never changed (warburton et al., 1973, Pallister et al., 1974, Nakagome et al., 1976, Robert et al., 1977, Wisniewski et.al., 1978). Centromeric deactivation is the most popular hypothesis ex, plaining type 2 dicentrics in.man, but other interpretations are possible. One theory held that the second centromere was submicro- sccpically deleted. Therman et a1. (1974) briefly discussed this possibility and.offered strong arguments against it. Hsu (1976) 20 pointed out that centroreric heterochromatin is not necessary for centrorere functioning, and only marks the position of these struc’ tures. Like all markers, absolute linkage cannot be assured. Soudek and Sroka (1977) felt that ro factual basis existed for inter- preting two C bands as an indication of dioentric structure. While this position may be valid in sore cases, the majority of reported rearrangements cotpel a dioentric interpretation on morphological grounds . 3d. Evidence suggesting a type 2 structure for inv dup(15) chrono- sores. The presence of two C bands on the inv dup(15) chromosotes sug- gests a type 2 dioentric structure. Supporting evidence is scant; only tie patient of Van Dyke et a1. (1977) was studied in an attempt to confirm this hypothesis. Nbrpl'ological peculiarities on the distal long arm have not been described by any of the investigators . Asym— metry of the polymorphism effectively marked both ends of tie bi- satellited chromosome in the patients of Rasmussen et a1. (1976) , Pfieffer and Kessel (1976) , and in four patients of Schreck et a1. (1977) . No shifts in the site of the primary constriction were roted in any of these cases. This might be explained by the general rule of centroteric dominance in type 2 rearrangerents, but may also indicate absence of a distal centrorere. 4a. Cytological mechanisms related to inv dup(15) . Several earlier observers suggested an origin by simple translo- cation and abnormal meiotic disjmction (Pfieffer and Kessel, 1976, 21 Rasmussen et al., 1976, Crandall et al., 1973, Watson and Gordon, 1974, Power et al., 1977) . According to Watson and Gordon (1974) , if both sets of satellites arose from different acrocentric chromosores (nonhorologs) , a chain four tetravalent and 3:1 disjunction could have occurred. Rasmussen et a1. (1976) commented that a dioentric arising from nonhorologous acrocentrics might undergo "centroteric noncoordiration" in meiosis, resulting in an aneuploid gamete. Van Dyke et a1. (1977) and Schreck et a1. (1977) introduced mechanisra consistent with the antiv-Sv-methylcytidine banding data. Van Dyke et a1. dismissed the possibility of centric fusion or parental inversion heterozygos ity , and proposed a mechanism involving non- sister chroratid exchange. According to this model, an abnormal exchange between two homologous , but nonsister chroratids , connected the two number 15 centromeres in meiosis I. At anaphase I, the attached number 15 chrorosotes were pulled entirely to one pole; one daughter cell was formed without any chrotosore 15 material, while the other received two normal now-sister chromatids and the dioentric. The second division then yielded a rormal gamete and a dioentric bearing gamete. Schreck et a1 . presented five mechanisms , all involving a meiotic exchange and rondisjunction. l) A recently broken chromosore 15 could have undergone sister strand reulion, and then nondisjoined with its rormal homolog. This mechanism would have produced diceno- trics with symretrical polymorphisms, a prediction rot consistent with sore patients (Schreck et al., 1977) . 2) An incorplete reciprocal translocation between two number 15 ' 5 could have produced a morocentric 22 bisatellited derivative, a number 15 with.a deleted short.arm, and an acentric long arm fragment. Given a chromoso'ral exclange of this type, patients would have inherited a number 15 with a deleted short arm» as well as the bisatellited derivative. A.chromatid exchange would have allowed the patients to inherit.a nonmal 15, as well as the bisatellited chromosome. The second alternative is consistent with the patients' karyotypes (Schreck et al., 1977). 3) A.U+type nonsister chromatid exchange, similar to that proposed by Van Dyke et a1. (1977) could have occurred. U-type exchanges are thought to arise from errors in crossing over, and have been documented in plants by JOnes and Brumpton (1971), and Brandham1(1975). 4) Crossing over within the loop of a paracentric inversion in a heterozygous parent could have produced a bisatellited dioentric. 5) Crossing over *within the loop of a pericentric inversion could have produced a bisatellited monocentric. If mechanism.5 were responsible, a peri- centric inversion should have been.detected due to an alteration in its anm ratio. This has not been the case (Schreck et al., 1977). .A paracentric inversion, on the other hand, could go undetected because of the unremarkable metaphase banding pattern present on the proximal portion of chromosome 15. van Dyke et a1. (1977) were unable to detect such an inversion in the parents of their case. Mechanisms 2, 3, and 4 seem the most consistent with the cases reported. It.would seemlattractive to relate the nondisjunction required by all mechanisms to centroreric deactivation in meiosis. However, there is no data available on this point. 23 Materials and Methods l. Ascertainment. Cases III and IV were ascertained during a dermatoglyphic study of an institutionalized, idiopathically retarded population in Michigan (Hassold, 1977) . The population consisted of 868 individuals, 77 of whom had an arch or radial loop on at least one thumb. 47 of these individuals were karyotyped at the Cytogenetics Laboratory , Hawtlorne Center, and 4 were subsequently referred to this laboratory for further study. Two patients presented with bisatellited super- nurerary acrocentrics, and were briefly described in Hassold (1977) . Cases II and V were not part of the study population, but were referred by the Hawtlorne Center laboratory because of similar find- ings. Case I was referred to this laboratory in 1972 because previous studies had suggested trisomy 22, a diagnosis inconsistent with her clinical findings. She was reevaluated in 1977 due to her resemblance to cases II through V. Case VI was ascertained for similar reasons. He was initially seen in our clinic in 1974, and cytogenetic studies suggested partial trisomy 22. Again, his clinical findings were not consistent with this syndrome. 2. Clinical Evaluation Data on the prenatal, perinatal, developmental, and medical histories of all patients were initially obtained from institutional and physicians' records, and in cases I and VI, our own clinic charts . This information was reviewed and updated during interviews 24 with the parents. A sister of case V served as informant since both parents were deceased. Biochemical , radiological , psychotetric , and EG evaluations were conducted by the various physicians or institutims caring for the patients . Red cell and serum polymor- phism data were supplied by the laboratory of Dr. Everett Lovrien, University of Oregon. Dermatoglyphic data were obtained from the study of Hassold (1977) , and by the author. Recent clinical findings reported below were observed during a 1977 physical evaluation of all patients performed by Dr. John Heffelfinger, Coldwater State Hore, Dr. James Higgins, Michigan State University, and the autl'or . To clarify the data available on published cases, auttors were contacted by letter and asked to review their patients with a clinical checklist we provided. This list was constructed using our patients as a model, but included a number of unrelated firdings. A ccpy of this checklist is enclosed in the Appendix. 3. Cytogenetics Short term peripheral blood culture were processed according to the standard method of morhead et a1. (1960) . Nodal karyotype numbers were established by a routine court of 30 cells stained with conventional 2% giemsa. Mosaicism studies were conducted on a variable number of metaphases stained with 2% giemsa, or with one of the banding techniques. The exclusion of mosaicism was calculated according to the tables of Hook (1977) . 25 Techniques for the induction of CBG, GIG, and QFQ7 bands were modified after Salamanca and Armerdares (1974) , Sun et a1. (1974) , and CaSpersson et a1. (1970) , and are described below. For GTG banding, flame dried slides were incubated overnight at 60°C, and then treated in a .025 M potassium pl'oSphate buffer with a pH of 6.8, for 1 to 10 minutes. A .l% trypsin solution was freshly prepared in distilled H20; slides were placed in this solution for 0.5 to 2 minutes, and then stained with 2% gismsa for 10 minutes. Metaphase spreads were photographed on Pan-X film at ASA 400 , and printed on Kodabromide #4 paper . For CBG bands, flamed dried slides were first treated in a .2N HCl bath at room temperature for 30 minutes . They were then placed in a 0.07N barium hydroxide solution at 40°C for 12 minutes. The HCl treatment was repeated for 15 minutes after rinsing. Slides were placed in a 2X SSC (pH = 7.0) saturated enviroment at 60°C for 14 to 20 hours. After rinsing, slides were stained in 2% giemsa for 15 minutes, photographed on Pam-X film at ASA 800, and printed on Kodabromide paper. For QFQ bands, flame dried slides were stained in a 0.5% atabrine solutim supplstented with 0 . 05 gm. quinacrine mustard for 8 to 12 minutes. Slides were briefly rinsed in distilled H20 for 15 secords, ard then placed in a citric acid/sodium plosphate buffer 7The 1975 supplement to the 1971 Paris Conference on nomenclature in huran cytogenetics established symbols for the various banding techniques then available. According to this norenclature: QFQ = Q bards by fluorescence using quiracrine; GI'G = G bands by trypsin using giemsa; RHG=Rbardsbyheatingusinggisraa; CBG=Cbandsby barium hydroxide using giemsa . 26 (pH = 5.6) for 1 minute. A ccverslip was mounted with the same buffer, and the slide plotographed urder UV illumination on Trio-X film. Metaphases were printed on Kodak Contrast 4 paper. A technique suggested by Passold (personal communication) was modified to produce RHG bards. Slides were prepared by airdrying, ard aged approximately 10 days prior to treatment. A citric acid/ sodium phosphate buffer with a pH of 5.05 was heated to 87°C. in a water bath. Slides were immersed in the heated solution for 25 minutes, ard immediately stained with 2% giemsa. Metaphase spreads were photo‘- graphsed on Panv-X film at ASA 800, and printed on Kodabromide paper. A sequential QFQ -> CBG technique was improvised. After standard preparation and microscopy, QFQ slides were destained in a 100% xylene ~> 70% EtOH --) EtOH sequence. They were then treated with the CBG technique, and metapl'ases were relocated using stage coordirates. Anti-S—methylcytidine banding was performed at Columbia University, New York, through the courtesy of Dr. O.J. Miller. The procedure is described in Schreck et a1. (1977) . QFQ and CBG polymorphisms were demonstrated with the above sequential technique . A conservative procedure for scoring acro— centric slort arm ard satellite polymorphism was adapted. QFQ poly- morphisms were scored in five cells from each irdividual according to the following criteria: 1 = not visible to dull 2 = bright 3 = intense A greater degree of subjectivity corplicated the scoring of CBG 27 polymorphisms. This was in part due to artifacts induced by the prerequisite sequential banding technique, and the limited number of cells in which acceptable results were produced. Three cells from each person were scored according to two criteria: 8 stall to medium L medium to large . Results 1. Cases Reports Case I (DD) DD is a 15 year old caucasian female. She was born to a 26 year old father and a para 3, gravida 2, 30 year old mother. During the course of the pregnancy, her mother suffered a chronic low grade viral infection . She also experienced severe emotional traura at the death of her father in the 4th month of gestation, ard was prescribed Milprsm for a period of one week. The delivery was at full term and uncorplicated. The birth weight was 7 1b. 3 02., and the length 19". The infant experienced croking spells after birth ard became cyanotic on the secord day due to aspiration of milk . Her early infancy was chracterized by poor development. She was hypotonic, inactive, and prone to ear infections; 22 were reported in the first year. Her sucking reflex ard growth were poor. She sat at 8 months, crept at 15 months, spoke single words at 2 1/2 years, and walked at 8 years. mntal retardation was diagnosed at age 2 1/2. DD' 3 behavior grew increasing hyperactive during early childhood. She was prone to witrdrawal , loss of contact, rapid mood changes , 28 .n Mandi. as Case I, DD. Figure 1. 29 disturbed mannerisms, ard frequent aggressive spells. Her gait was clumsy and characterized by toe walking. Hearing was normal and speech clear, but with marked perseveration and echolalia. An EEG at age 5 suggested right side brain damage and a possible seizure pattern. Her first grard mal seizure occurred at age 11. Anti- convulsant therapy included Dilantin and Phenobarbital , but the seizures continued: she has averaged 1 every 2 months. Her most recent EEG was mildly abrormal and suggested a mild seizure terdency. Sleep pattern was fairly well organized, but slowed a number of low amplitude miror theta and sharp wave transients in the left tsrporal region, with sore anterior temporal emphasis . The waking record showed a slight enhancement of fast activity. Physical examination at age 15 revealed the following: flat occiput, external strabismus, slightly depressed nasal bridge, short philtrum, lowset ears with a slight posterior rotation, minimal prograthism, slight proximal placement of the thumbs , increased carrying angle, webbing of toes 2 ard 3 bilaterally, lordosis, dark pigmentation, ard a strange gait. Reflexes, menstrual history, ard breast development were rormal. Her height was 142.3 on. (less than 3 s.d.) , ard head circumference 50.5 on. (less than 2 s.d.). SMAv-lz, CH3, and urinalysis evaluations were rormal. Her IQ was estimated as 35 on the Stanfordo-Binet scale. Her dermatoglyphics were as follows: left right 1 2 3 4 5 1 2 3 4 5 UWUUU UWUUU 30 thenar/ I open/ loop Open/Open II open open III Open open IV loop loop atd t t creases ronmal rorrmal DD's family history was negative for consanguinity, mental retardation, and congenital malformations. She has 3 rormal sibs, and her mother did not experience any miscarriages. Case II (CL) CL is a 26 year old caucasian male. He was born to a 38 year old father and a gravida 5, para 3, abortus 1, 36 year old mother. The pregnancy was full term with an unremarkable delivery. The birth weight was 9 1b. 8 oz., ard no abnormalities were noted. His sucking reflex ard appetite were good, although frequent enemas were required during the first to years for bulky stools. An an infant, he failed to make eye contact, ard had infrequent spontaneous movstents. He was hypotonia , rolled over at one year, walked morally at two years, spoke recognizable words at four years, ard las never been toilet trained. In early childtood, he became increasingly hyperactive and aggressive , and was committed to an institution for the mentally retarded at age 5 . The following features were noted upon admission: height, weight ard head circum- ference values all above the 25th percentile, enopthalmos, a soft systolic murmur in the mitral valve area, cryptorchidism, a voice 31 Figure 2. Case II, CL. 32 but no speech, ard hyperactivity. The heart murmur ard cryptor- chidism were not detected in later exams. Shortly after cormitment, he experienced his first grand mal seizure. Isolated seizures occurred througlout late childhood, and became very frequent in adolescence. An EEK; at 17 showed poor organization and background fast activity. Seizure discharges and sharp waves were noted. He was given Dilantin and Mellaril, but would not tolerate Pherobarbital. In October, 1969, brain damage associated with repeated daily seizures confined him to a wheelctair. Afterwards, the frequency of seizures diminished, with the last reported in October, 1976. His beravior is now subdued, and his condition described as stable. Physical examination at age 26 revealed the following: prominent forehead with heavily scarred supraorbital ridges , antimongoloid slant, enopthalmos, recessed slort upper lip, short philtrum, prolonged chin, increased carrying angle , mild intention tremor of the right hard, minimal flexion contractures of the knees, webbing between toes 2 and 3 bilaterally, and stall scrotal cysts. An ex- cessive breath and body odor was also roted. His height was 164 om. (less than 3rd percentile), and his head circumference was 60.3 om. (50th percentile). Skull and chest X-rays were rormal. His IQ was established as 16 on the Stanford Binet scale. His dermatoglyphics are summarized below. left right 1 2 3 4 5 1 2 3 4 5 A R U U U U U U U U 33 thenor/ I Open/open Open/open hypothenar open open II Open open III Open open IV open open atd t t creases rormal normal CL's family history is negative for congenital malformations, mental retardation, and consanguinity. He has 3 rormal sibs. His mother's first pregnancy ended in a first trimester spontaneous abortion . Case III (ML) ML is a 17 year old caucasian male. He was born to a 38 year old father ard a gravida 4, para 2, aobrtus l, 38 year old mother. The pregnancy was oorplicated by an episode of bleeding lasting for one week in the third month. The delivery was at full term and uncompli- cated. The birth weight was 7 1b. 4 oz., ard ro abnormalities other than a shrill cry were roted. He sucked well and had ro feeding problems. ML was described as a hypotonic, irritable infant wro disliked being touched. He sat at 10 months, walked at 15 months, ard had poor speech develogtent. His gait was clumsy and he fell frequently. A diagrosis of cerebral palsy was offered at age 4. He became in,- creasingly self abusive, aggressive, and hyperactive, and was unable to atterd special education classes because of behavioral problems. 34 Figure 3. Case III, ML. 35 He was placed in an institution for the mentally retarded at age 9. He experienced his first grard mal seizure at the age of 10 following a blow to the head. He was hospitalized for observation, but an EEG showed no abrormalities. Nbre seizures occurred in early adolescence; an EEG at age 15 was slightly abnormal, ard suggestive of a diffuse disturbance of brain function. At age 16, he urderwent psychiatric evaluation because of frequent seizures . His last reported seizure occurred in September, 1977, but it is unclear whether the frequency is diminishing. His present medications con— sist of Valium, Pherobarbital, and Malox for a duodenol ulcer. Physical examination at age 17 revealed eroptlalmos, epicanthal folds, minimal antimongoloid slant, external strabismus, slort philtrum, a high arched palate, pointed overbite, prolonged chin, thickened asymmetrically placed ears, facial asymmetry due to hemi- paresis, arched placement of the digits into the palms, increased carrying angle, ard clirodactyly. Hemiparesis was present with the greatest muscle tone on the right side. Scoliosis was suggested, but likely due to a pelvic tilt ard a definite size difference between the legs. Slight spasticity in the legs was also noted. Hearing and sight were normal, and speech was clear, but for the most part parroted. He was hyperactive, self abusive, and frequently aggressive. Urinalysis, CBC, and radiological evaluations were rormal . His IQ was estimated as 25 on the Stanford-Binet scale. His height was 170.2 on (25th percentile), ard head circumference 54.6 (greater than 2 s.d.). His dermatoglyphics are sumarized below: 36 left right 1 2 3 4 5 1 2 3 4 5 U A A U U R A A U U thenar/lst open/open Open/Open II open B and ‘C triradii displaced medially with a loop inbetween III Open IV open Open atd t t creases rormal rormal ML ' s family history is negative for mental retardation, congenital malformations, and consanguinity. His mother's first pregnancy ended in first trimester spontaneous abortion. He has 2 rormal sibs. Case IV (RF) RF is a 49 year old caucasian female. She was born to a 34 year old father and a gravida 3, para 1, abortus 1, 34 year old mother. The pregnancy was corplicated by two instances of first trimester hetorrhaging, an acute gall bladder infection accorpanied by bron- chitis in the 7th month. The birth was one month prerature, with an uncorplicated delivery. The birth weight was 6 1/2 lb. , and ro unusual features were roted. Her sucking reflex ard appetite were good. Early infancy was unretarkable until the 10th week, when RF developed inf luenza and an ear infection. Oonvulsions occurred for two days, followed by a terporary paralysis. Her recovery was slow, and the convulsions did rot recur. 37 Figure 4. Case IV, RF. 38 RF was an inactive, hypotonic infant. She sat alone at 13 months, walked at 2 years, ard spoke single words at 3 years. Her gait was awkward, and characterized by toe walking. Speech was infrequent, usually unintelligible, ard softly spoken. Early childlood was dominated by hyperactivity and unpredictable aggressive episodes . She was placed in an institution for the mentally retarded at the age of 6. RF suffered grand mal seizures for a period of 12 years, begin- ning at age 18. They were most frequent at age 20-21, ard occurred at intervals of 2 to 3 weeks. Her last reported seizure was at age 31. An EEG at age 39 slnowed sl'ort bursts of spiked discharges and bifrontal abnormalities or seizure discharges. She had been treated with Dilantin and Phenobarbital since age 19. RF's first 20 years of institutionalization were dominated by behavioral problems , principly hyperactivity and aggression. In the last two decades however, her behavior has becore subdued ard slne is presently considered ronaggres- sive, cheerful, and cocperative. She is a self feeder, corpletely toilet trained, has rormal mobility, but little recognizable speech. Physical examination at age 48 revealed the following: stall palpebral fissures , minimal antimongoloid slant, slightly lowset ears, a high arched palate, hypoplasia of the left side of tlne face, a low posterior hairline, increased carrying angle, proximally placed thumbs, proximally placed 5th toes, webbing between toes 2 and 3 bilaterally, and a high instep. Her reflexes were depressed at the knee ard ankle , but otherwise rormal . There were multiple pigmented nevi on the face ard trunk, ard a dark cotplexion. Her height was 39 155 on. ard head circumference 55.2 cm. Urinalysis, CBC, ard radica- logical evaluations were rormal. She has had mural menses since age 14. Her IQ was estimated as 24 on the Stanford-Binet Scale. Her denratoglyphics are summarized below: left right 1 2 3 4 5 l 2 3 4 5 A A U U U U A U U U thenar/lst pattern/ Open Open/Open II Open open III open Open IV pattern pattern atd t t creases normal normal RF ' 5 family history is negative for mental retardation , congenital malformations, ard consanguinity. A cousin of the maternal grand» mother had epilepsy. RF lnas two rormal sibs. Her motler's second pregnancy ended in first trimester spontaneous abortion . Case V (EL) EL is a 27 year old black female. She was born to a 40 year old father and a gravida 4, para 3, 35 year old mother. The pregnancy was full term with an unremarkable delivery. The birth weight was 6 1b. No abnormalities were roted in early infancy. She was rot hypotonic, but was considered slow by family members. At the age of 1, she suffered a high fever. No convulsions occurred, but it was reported that her right hard was held at an odd angle afterwards. She recognized her parents at 1 1/2 years, sat alone at 2 years, 40 Figure 5. Case V, EL. 41 walked at 4 years, was toilet trained at 8 years, and spoke single words at 10. .Menses began at 10 1/2. Her gait was initially abnormal, and characterized by toe walking. In late childhood, her behavior grew increasingly hyperactive and aggressive, and she was institutionalized at the age of 12. Upon admission, her weight was 38 kg., height 146 cm., and head circumference 52.7 cm. The only physical abnormality noted was irregular dentition. Her height at age 17 was 147 cm” (less than 2 s.d.), and head circumference 54.6 cm. (50th percentile). Physical examination at age 27 revealed the following: small forehead, flat occiput, periodic nystagmus, external strabismus, short philtrum,lowset small posteriorly rotated ears, malocclusion, hair growth on the chin, lack of breast development, increased carrying angle, clinodactyly, camptodactyly, arclned placerent of digits into the palms, proximally placed 5th toes, webbing between toes 2 and 3 bilaterally, lordosis, and an awkward "tin soldier" gait. Her menstrual history was rormal. Speech developrent was restricted to a few words. She was chronically abusive, hyperactive, and de- structive. The results of SMAr12, CBC, urinalysis and radiological evaluations were nonmal. There was no indication of seizures in her history, and her EEG's were normal. Her IQ was estimated as 8 on the StanfordrBinet scale. Her dermatoglyphics areesummarized below: left right 42 thenar/lst open/open open/open II Open open III pattern Open IV pattern pattern atd 60° 60° creases normal normal EL' 3 family history is negative for mental retardation, congenital malformations, and consanguinity. She had a total of 5 sibs. The first died at age 3 months of unknown causes. Two were twins of unknown zygosity; one twin, altlough fully formed, was stillborn. The retaining sibs are normal. No spontaneous abortions were noted. Case VI (TM) TM is a 3 1/2 year old caucasian male. He was born to a 24 year old father and a gravida 5 para 4, 28 year old mother. During the pregnancy, his mother experienced frequent heartburn ard headaches, for which she took approximately 4 1/2 teaspoons of baking soda a day, and approximately 24 aspirins a week. A fever of 104° in the 3rd month was treated with Nyquil. TM was born at full term. Respiration was immediate and spontaneous, ard no abnormalities were roted. He weighed 10 1b. 12 02., with a length of 55.9 cm. (3 s.d. above norm), ard a read circumference of 36.8 on. (50th percentile). Feeding was difficult for the first 3 months due to a poor sucking reflex. He reacted poorly to sight and sound, and was inactive and hypotonic . Physical examination at 5 months revealed no obvious malformations . He lad weak muscle tone, hyperactive deep tendon reflexes, and was unable to support his head or roll over. An EEG 43 Figure 6. Case VI, TM. 44 showed generalized slowness and excessive beta and fast activity. Hyperactivity, gross delay of developtental milestones, ard probable profound mental retardation were evident upon reexamiration at age 3 1/2. Sight and hearing appeared normal. The following features were noted: minimal epicantlal folds, external strabismus , high cheek bones, antiverted rostrils, posteriorly rotated ears, clinodactyly, slight proximal placement of the thumbs, tapered thumbs and big toes, slightly increased carrying angle, ard webbing between toes 2 and 3 bilaterally. His length was 88.9 on. (less than 10th percentile), and head circumference 47 on. (less than s.d.) . Fasting blood and electrolytes, Multi--20, fundoscopy, Torch, ard radiological evaluations were within normal limits . His dermatoglyphics are surmarized below: left right 1 2 3 4 5 1 2 3 4 5 U W A U U U R U U U Therar/lst open/open open/open II open open III loop loop IV open open atd t t creases rormal normal TM' 5 family history is negative for congenital malformations, consanguinity, and mental retardation . His mother l'ad four normal children by her first marriage, and one rormal child, in addition to TM by her second marriage. She has rad ro miscarriages. 45 2. Surmary of phenotypic findings. The clinical findings in cases I—V are presented in Table 5. Case VI is not included because his chrorosomal abnormality differs from the others. 3. Linkage studies. Data on red cell and serum polymorphisms were obtained from patients and their parents. This information is summarized in Table 6. No segregational anoralies were observed in these families. Biochemical studies were not performed in cases IV and V because one or both parents were uravailable . 4a. Cytogenetics of cases I—V. A preliminary evaluation of 30 cells from each patient revealed a modal count of 47 + acrocentric marker, and ro evidence of mosaicism. The extra chrorosomes had terminal satellites on both arms, ard were somewhat larger than a number 22 (Figure 7). Both arms were observed in satellite association, but rarely at the same time (Figure 8). QFQ, GIG, andRHGpatterns inthemedialportionof theextra chromosomes were identical in all five patients (Figures 9--11) . The QFQ pattern was consistent with proximal 13q ard 15q, less consistent with 14q, and inconsistent with chrorosores 21 and 22. RHG produced a moderately dark medial bard consistent with proximal l3q and 15q, but rone of the other acrocentrics. The GIG pattern resembled 15pter -9 15q21, ard a faint band similar to 15ql4 was present at the midpoint of the markers in early metaprase preparations. 46 Table 5. Phenotypic findings in cases 14v. Case I II III IV v Sex F M M F F 3F/2M Age 15 26 17 49 27 Birth Weight (Kg.) 2.7 3.6 2.7 2.5 2.2 Flat Occiput + - w - + 2/5 Low Posterior Hairline + - _ + ~ 2/5 Facial.Asymmetry w _ + + , 2/5 Antimongoloid Slant - + + + ~ 3/5 Enopthahmcs - + + — w 2/5 Strabismus + a + ~ + 3/5 Nystagmus - - - — + 1/5 Short Philtrum + + + _ + 4/5 Malocclusion w _ - - + 1/5 High Arched Palate w w + + - 2/5 Prolonged Chin w + + - w 2/5 Imset Ears + - + + + 4/5 Malformed Ears ’ w + r w 1/5 Rotated Bars + - + e + 3/5 Increased Carrying Angle + + + + + 5/5 Clinodactyly w w + — + 2/5 Proximally Placed Thumbs + a w + _ 2/5 Ab. Dermatcglyphics - + + + + 4/5 Webbing Toes 2 and 3 + + ~ + + 4/5 Lordosis + m — r + 2/5 Normal Menses + + + 3/3 NOrmal Breasts + + w 2/3 Dark Pigmentation + a — + _ 2/5 Short Stature + + e - + 3/5 Mental Retardation + + + + + 5/5 Hypotonia + + + + ~ 4/5 Aggressive Behavior + + + + + 5/5 Seizures + + + + _ 4/5 Abnormal EEG + + + + w 4/5 Abnormal Gait + w + + + 4/5 The walking + — — + + 3/5 Maternal Age 30 36 38 34 35 34.6 Paternal Age 26 38 38 34 40 35.2 Hyperactivity + + + + + 5/5 Developmental Retardation + + + + + 5/5 muse unease. m%I(W) AMYZ a &%IH@I ogaeg QEEESTF » agwadgrm 0 Us) Ema g twang tyOli ...; II’Ir-‘IP't-‘C.’ ppHH ...: "Ill-4 U) was U $5.? lamg prHwHwHCNOI H I'1'.Il~---I U) S m Wééw prHgHCpni+gw H H HT”? H H U) >HvHoNOIi$ww§8>8 pHH |.—ul wggg 9 mH> m E I H meHHHpHpHCNnI+>w Table 6 (continued) Case III (ML) Father U) o HHHHpHgC‘. i +wa§8O 48 HHHmpngi-l-tvtow Cce {VI-49C} i +1P'5WE U) m I |._.: HHHN 49 H .5 A. a. to 6 5 C C I Figure 7. Conventional giermsa staining. pr: normal D and G group autosores. Bottom: inv dup(15) from cases I—V. I \ l \ 0,. _ '0 9 ¢ Figure 8. Inv dup(15) in satellite association. Figure 9. QFQ staining. Top: normal D and G group autosomes. Bottom: inv dup(15) from cases Io-V. 50 t. a! .0 I. Figure 10. GIG staining. Top: normal D and G group autosomes. Bottom: inv dup(15) from cases I--V. :. 1i ‘i .0. C. I 9 5 O a Figure 11. RHG staining. Top: normal D and G group autosomes. Bottom: inv dup(15) from cases I-V. Q. Figure 12. CBG staining. Top: normal D and G group autosomes. Bottom: inv dup(15) from cases I-V. 51 CBG banding revealed two heterochromatic regions, one correspond, ing to the sl'ort arm, and a secord located proximal to the satellites on the long arm (Figure 12) . The distal CBG band corresponded to the distal GIG band resembling 15q21 (Figure 10). The distal CBG bard varied in size within the same irdividual. In early metapl'ase, proximal ard distal bards were visually equivalent. In many late metaphases, the distal bard was sraller than the proximal band. A similar pattern was also observed in the distal satellites, although these structures are less amendable to quantification. A difference between the condensation rates of the proximal and distal regions is the most likely explanation for these observations . We tentatively conclrded that the bisatellited chrorosores represented abnormalities of l3q or 15q . Interpretation of the rearrangerents was corplicated by the CBG results. Three possible structures were postulated: 1) A deleted acrocentric morocentric with an acrocentric stort arm translocated to its distal end. 2) An asymmetrical dioentric formed from an end to end translo- cation of two deleted acrocentrics . 3) A symmetrical dioentric formed by a U-type excrange. The identity of the bisatellited chrorosores was clarified by anti=-5’-methylcytidine banding, and an analysis of pclyrrorphisms. Antics-methylcytidine banding produced two regions of intense staining correspording to the CBG bards on each marker. This irdicated that both regions were corposed of chrorosore 15 sort arm material, and by interence, tlat the medial portion contained chrorosore 15 long arm 52 euchromatin (Miller et a1. , 1974, Schreck et al., 1977) . In all five cases, proximal ard distal QFQ satellite polymorphisms were asymmetrical, and therefore inconsistent with an origin by sister chromatid exchange. Since these pclyrrorphisms also marked the Opposing ends of each chrorosore, it was possible to detect any shifts in the location of the primary constrictions. None were observed. QFQ and CBG polymorphisms were then analyzed for information bearing upon the identity and origin of the markers. In cases I-III, rormal acrocentric pclyrrorphisms were corpared to tlose of the bi- satellited chrorosores. A number of rormal acrocentrics were excluded as possible contributors on the basis of visible dissimilarities. The results of this corparison are given in Table 7. The order of the parental chrorosores correspords to the order of their appearance in the partial karyotypes (Figures 13-15) .3 A similar procedure was applied in cases IV and V, although only the patients' normal acrocentrics were available for corparison. The results are given in Table 8. Again, the order of the rormal acro- centric ccrrespords to their appearance in the partial karyotypes (Figure 16). Thedata inTables 7ard8were thenusedtodeterminewhich Egg of acrocentrics could have contributed the polymorphisms ob- served on each of the bisatellited chrorosores. This process is illustrated by the following example . In case I , polymorphisms on a maternal 14, 15 ard 21 were similar to the proximal polymorphism on 8Scores assigned to each chrorosore are listed in the Apperdix. 53 60335 no: u + .aheoouoemaoo Em once begin n o .emeogeoo Euro bacon gamma u o + + + + + + + + + >mmm0 + + + + + + + QNN MNN DAN MAN Ema Home QvH ova an MMH CLO“ CLO" >H mmmu .> Ufim >H 8mg 5 mHOUHnHfiCB mm Hamid—HUNG ”HOG mUflHUCQOOHUM HQFHOZ .m wflflmfi .8305 so confided odds at 8885 uoc n .+ .8888 no: u + anaconda {fled Em once ggcaom u o Showdowns—Enos and bacon Egon—doom u o .HmcHoumo u m JESSE: u a + o + + .+ + .+ + .+ .+ o HHH onto + o .+ + .+ + .+ d H mono + + .+ o + .+ .+ o Honda 2 o a z z o o. z z o o z z a o 2 z o o mm am we we ma .HHHrH mommo 5 nuouoflwucoo mm ooooeoxo uoc moeuucooouom Hmcfioz .n manna 54 a.;~g;i“f~“““'.'..«‘.7‘ "”33: an... . .Hms--W‘JM.N Figure 13. QFQ polymorphisms in family of DD. Top: paternal. Middle: maternal. Bottom: DD. H ctr: .... " " 7' r " Figure 14. QFQ .. CBG polymorphisms in family of CL. Upper photo, QFQ. Top: paternal. Middle: maternal. Bottom: CL. lower Photo: same chrorosores with CBG staining. 55 . .1. . ‘1 _ 1.... .01: .---._-*j-fg'=»"wl.-r"ff" ' "or, .-,.3~_ :7 or» ' '51:.915 "fivffj'a—fialb 1.1:»: ' "9"“ _. a Figure 15. QFQ polymorphisms in family of ML. Top: paternal. Middle: maternal. Bottom: ML. Figure 16. QFQ polymorphisms in cases IV and V. Top: RF. Bottom: EL. Figure 17. QFQ polymorphisms in family of TM. Top: paternal. Middle: maternal. Bottom: TM. 56 the proband' s bisatellited chrorosore. The only maternal acrocentric with a polymorphism similar to the distal polymorphism on the bi- satellited chrorosore, was a nurber 15. Therefore, materral 14/15, 15/15, or 21/15 rearrangerents could have given rise to the marker. The same reasoning was applied to each person aralyzed, ard the results are given in Table 9. In case II, involvement of at least one number 15 was indisputable. The distal end of the bisatellited chrorosore was marked by a brilliant satellite present only on a maternal 15. Polymorphisms in cases I and III also irdicated involvement of at least one number 15. In all three, a 15/15 rearrangement was one of the possibilities consistent with the data. In cases II ard III, only maternal chromosomes were likely to have participated in the rearrangerent. In cases IV ard V, involverent of number 15 colld not be deter- mined from the limited data. Both patients inherited normal 15's with polymorphisms similar to tlose on their bisatellited chrorosores, an observation not inconsistent with the anti-S—methylcytidine results. In case V, the proximal polymorphism of the bisatellited chrorosore did not match any of ttose present on normal acrocentrics. This irdicated a meiotic origin. The exclusion of mosaicism, according to the calculations of Hook (1977) , is given in Table 10. No dioentric chrorosores, or fragments of a possible anaphase bridge origin were observed. Although the long arm chromatids of the bisatellited chrorosores were generally held in a characteristic parallel position (Figure 7), constriction- 1ike abrormalities were rot observed at their distal ends. As pre- viously roted, the primary constriction in each did rot vary in 57 Table 9. Possible rearrangements giving rise to supernumeraries as determined from tables 6 and 7. Maternal Paternal Mitotic Case I 14/15 15/22 14/15 15/15 15/15 15/22 Case II 14/15 NOne None 15/15 Case III 14/15 NOne NOne 15/15 15/21 15/22 Case IV ? ? 14/14 14/15 14/21 14/22 Case V ? ? NOne 58 Table 10. " The highest level of mosaicism excluded in patients with .95 and .99 confidence levels. Cells .95 .99 Parents (all) 50 6% 9% Case I 350 1% 2% Case II 206 2% 3% Case III 279 2% 2% Case IV 330 1% 1% Case V 100 3% 5% Table 11. Possible rearrangements giving rise to the supernumerary in case VI as determined by familial polymorphisms. 15/ 21 Maternal Paternal Mitotic 14/14 14/ 15 14/ 14 14/15 14/22 14/15 14/21 15/22 14/ 22 15/15 15/15 15/ 22 59 position. There was no evidence of paracentric or pericentric inversion of chrorosore 15 in standard metaphase preparations from any of the parents or patients. Parental karyotypes in all cases were rormal. 4b. Cytogenetics, case VI. A preliminary evaluation of 30 cells from case VI revealed a modal count of 47 chrorosores with no evidence of mosaicism. The extra chrorosome was an acrocentric somewrat sraller than a number 21, and characterized by terminal satellites on both arms (Figure 18) . Either end of the marker participated in satellite association; both ends were never observed in association at the same time. CBG banding revealed only a single large proximal heterochroratic region, even in prometapl'ase spreads. The intensity of the QFQ long arm pattern was most consistent with the proximal portions of l3q and 15q. It was less consistent with l4q, ard inconsistent with chrorosores 21 ard 22 (Figure 17) . The GTG technique produced relatively poor banding even with repeated trials; observed patterns were essentially devoid of landmarks. The entire long arrm was lightly stained, with intense banding only at the centro- mere ard short arm. The overall pattern was consistent with all the acrocentrics except number 21. The RHG technique produced moderately dark staining on the entire long arm, and was consistent with the proximal portion of 15q. Anti—S-methylcytidine banding produced intense staining on the marker's short arm. A trace amount of banding was observed at the distal tip of the long arrm (O.J. Miller, personal communication) . 60 to 0 Figure 18. Extra chromosome incaseVI shownwitharormangroup for size corparison. Top: conventional giemsa. Bottom: RHG staining. 61 An analysis of polymorphisms was corducted using the same format established in cases Iv-V. Unlike these cases, the terminal satellites were stained with equal intensity, and did not excltde a sister chrora~ tid exchange as a possible mechanism. A corparison of familial QFQ and CBG polymorphisms can be fourd in the appendix. The results were ambiguous, but did exclude chroro- sore 13 from the rearrangerent. Possible rearrangerents consistent with the polymorphism data are listed in Table 11. An evaluation of 50 cells from each parent, ard 100 cells from the patient did rot reveal evidence for additioral cell lines or inversion heterozygosity. The evidence obtained on this patient is consistent with the following interpretation: t(15;15) (p11;q14 or 15) , but others may be proposed . Discussion 1a. Identification of the bisatellited chrorosomes. Six patients with de rovo bisatellited acrocentric supernumeraries were evaluated with a combination of five banding techniques. QFQ, GIG, RHG, and CBG procedures produced identical firdings in cases I—-V. Each bisatellited chrorosore had a single primary constrictior and two terminal CBG positive regions, presurably corposed of acrocentric short arm material . The medial euchroratin bordered by these regions had so, so, ard RHG patterns consistent with 15q11 ..., 15, and to a lesser extent, proximal 13g. The marker in the sixth patient did not have a distal CBG band ard was sorewhat sraller, but in other respects, 62 resembled the first five. Anti-Serethylcytidine banding was performed in all cases because of its ability to differentiate chromosome 15 material fromrother acrocentrics. Both CBG positive regions in the first five patients banded with this technique, indicating a complex origin from chromosome 15. The sixth marker stained on its short arm, and also at the tip of its distal long anm, suggesting that it might represent a variant form of the larger bisatellited chromosomes. Chrorosore polymorphism studies ccnfirrred much of the anti-5- methylcytidine data in cases I-III. Asymmetrical QFQ polymorphisms on each supernumerary ruled out an origin by sister chromatid exchange. QFQ and CBG preparations indicated that at least one chromosome 15 had contributed to the bisatellited derivatives, but did not establiSh the specific identity of the secord chrorosore involved. Anti’Sc methylcytidine studies had indicated that a 15/15 rearrangement was present, and the polymorphism data were consistent with this inter- pretation. In cases IVHVI, polymorphism.data were limited. However, no inconsistencies with the antics-methylcytidine results were evident, and a sister chromatid exchange was ruled.out by asymmetrical QFQ polymorphisms in cases IV and V. From.these observations we concluded that the extra chromosomes in cases I-V were identical with markers studied in six patients by Schreck et a1. (1977). Following their nomenclature, the bisatellited derivatives are designated inv dup(15)(pter -9rql:pl or ql -9rpter). Torour knowledge, the extra chromosome in.case‘VI has not.been.pre- viously reported. It is tentatively described here as t(15;15)(pll; q14 or 15) . 63 lb. Further characterization of the inv dup(15) chrorosore. Three alternative structures can be proposed (see Figure 19) . l) t(15;15) (pll;q15): a nonocentric derivative produced by trans,- location of short arm material from one number 15 to a breakpoint at q15 on the long arm of the second number 15. This represents a proximal trisomy of 15q, and a partial tetrasomy of 15p. 2) tdic(15;15) (q;q): a dioentric derivative produced by translo- cation of the short arm, centromere, and proximal long arm from one number 15 to a breakpoint on the proximal long arm of a second number 15. The breakpoint on the first number 15 would lie proximal to band 15ql4, and on the second number 15, distal to this band. The rearrangement would represent a proximal trisomy/tetrasamy of 15q, and a full tetrasomy of 15p. 3) tdic(15;15) (ql4;ql4): a dioentric derivative produced by a U type exchange or symmetrical translocation involving two number 15 ' s . It represents a tetrasomy for 15pter ~+ 15ql4. Current metaphase banding techniques lack sufficient resolution to distinguish between these alternatives. Of bands lSqll » lSqlS. only lSql4 is consistently reproduced in RHG and GTG preparatio . A similar band is present on the inv dup(15) , but none of the proposed structures require a change in its position or appearance. Prometa- phase banding techniques may be useful in solving this problem, once they are adequately developed. The demonstration of a second centrarere would eliminate option 1 . Dicentric studies have been reported in one previous case (Van Dyke et al., 1977) . An additional fragment was interpreted as the e .0 ”a 11! and B t(15:15) (pll;q15) 64 V V Lei! H H F“; tdic (15:15) (q7q) tdic (15:15) (ql4;ql4) Figure 19. Alternative structures for inv dup(15) . 65 product of a bridge‘breakage—fusion cycle due to reactivation of the inv dup(15) '3 second centromere. In our patients, semi-constricted long arms, distal primary constrictions, or other morphological abnor- malities were not observed. Furthermore, there was no indication of the mosaicism described by Van Dyke et a1. (1977) . Certain characteristics were noteworthy. Satellite polymorphisms marked the opposing ends of each inv dup(15) , making it possible to observe any shift in the position of the primary constriction. None were noted. Asymmetrical QFQ and CBG polymorphisms were also described in seven previous cases (Schreck et al., 1977, Pfieffer and Kessel, 1976, Rasmussen et al., 1976, Centerwall and Morris, 1975) , and no inconsistencies were noted. In our patients, inv dup(15) long arm chromatids were held in a characteristic parallel attitude, whereas similar sized G group chromosomes tended to have widely separated chromatids. In early metaphase, the size of the inv dup(15) proximal and distal CBG bands were generally equivalent. However, the distal band seemed to decrease in size more rapidly than the proximal band as metaphase progressed. This was also true of the distal satellites; they became increasingly more difficult to resolve in later periods of metaphase, when compared to the proximal satellites. This pherom- ena seems to reflect an abnormal change in the rate of condensation of the distal-most regions, a characteristic also observed in a pre- vious case of a type 2 autosomal dioentric (Wisniewski et al., 1978) . Prerature condensation of the distal-most regions may be related to a mechanism allowing maintenance of iractive centromeres. However, this point must be confirmed in later studies. All five inv dup(15) chrorosores described in this report did not display morphological 66 characteristics associated with type 2 dicentrics, with the possible exception of centromeric dominance. We must conclude that current data is insufficient to resolve the number of centromeres on these rearrangements . 2a. The inv dup(15) phenotype, cases I-V. The developmental histories of our patients were remarkably similar, and perhaps the most characteristic aspect of this disorder. Four of the five pregnancies were full term, and all birth weights were appropriate for gestational age. No abnormalities of any sig- nificance were noted at birth or in the neonatal period, although two infants experienced feeding problems due to a poor sucking reflex. Hypotonia and/or developmental retardation were noticeable in the first year. As infants and young children, our patients were generally inactive and lethargic. In two cases, indifference to external stimuli prompted questions of possible sensory impairment. Developmental milestones were grossly delayed in all five children. Speech and toilet training were never achieved in two. Four walked with an awkward gait, and three were toe melkers. Bew- tween the ages of 4 and 6, each of our patients grew increasingly hyper, active , aggressive , and unpredictable . Mental retardation was obvious; all five were eventually too difficult to manage in the home environ, ment, and were institutioralized. Because of past medical histories, gait abnormalities, and the absence of congenital malformations, diag- nostic workups tended to favor disorders related to postnatal insult. Four of the five patients developed a convulsive disorder in the institutional environment. The age of onset ranged from 5 to 18 , 67 and the frequency of seizures tended to increase with age throughout adolescence. In the two older patieits, the disorder gradually disappeared, and recent EEG' s were interpreted as normal. A reduction in hyperactivity also roughly followed the abatement of seizures . The remaining two cases with seizures appear to be following the same general course . The patient who never developed a convulsive dis- order has retained chronically hyperactive and abusive. All five patients are mentally retarded, two profoundly, and three severely. The belavior of our least retarded case (Case I) resembles that of the patient of Rasmussen et a1. (1976) who was diagnosed with infantile autism. All five patients are free of major life threatening defects, and enjoy generally good health. It is important to note that the mildly dystorphic features in these patients were recognized only after careful examination. The facies was not strikingly dystorphic. The head shape was suggestive of a mild dolicocephaly, with the visual impression of bitetporal narrowing. A flat occiput was noted in two patients. Facial abnor- malities often included strabismus, slight antimongoloid slant, sl'ort philtrum, and slightly lowset ears. Enopthalmia, facial asymmetry, high arched palate, prolonged chin, malocclusion, and malformed ears were seen in one or two cases. Neck and trunk deformities were absent except for low hairlines and lordosis in two patieits. Uro- geiital anomalies were catpletely absent, as were heart defects. Certain minor limb malformations were noted. The carrying angle in all our patients was increased. Proximal placement of thumbs, and 68 Clinodactyly were occasionally seen. In two patients, the placerent of digits into the palm appeared more arched than usual. Dermatoglyphic abnormalities were present, but in a nonspecific fashion. Arches or radial loops were observed on digits other than number 2, and case V had elevated atd angles. The legs and feet were generally unremarkable. One patient had a high instep (probably familial), and two had proxi- mally placed fifth toes. Four of the five had webbing between the second and third toes bilaterally. Short stature was observed in three patients, but true microcephaly was not. Neurological findings were essentially normal, as were the results of EMA—12, CBC, urinalysis, and radiological studies. A few unusual features were noted. Two patients had dark skin pigmentation, a trait recognized by, but not in, their families. One had a normal menstrual history, but lacked breast development. One patient had a mild hemiparesis, while another had a peculiar per- sistent breath and body odor. 2b. The inv dup(15) syndrome. A total of 19 cases likely to lave the same inv dup(15) chroro- some as our patients were ascertained in the literature. Seven of these have been confirmed by antic-Svmethylcytidine banding (Schreck et al., 1977, Van Dyke et al., 1977) . The remaining 12 (see Table12) carpare well with the cm, QFQ, and CBG findings in our five cases, and the seven previously confirmed. We feel that there is little uncertainty in considering all as examples of the same chromosome abnormality, an assumption strengthened by phenotypic considerations 69 m\N + I + I I I I I mHmOHHoom OH\m I + + + + I + I I I ououmum unonm m\o I I I I I o~mc<.mce>uumu o\m I + I + I I m o m 88. mfioows m\o I I I I I woos Hmeexopm m\o I I I I I ensure Hmeaxoum o\H I I + I I I waxuomooceau m\H I + I I I I mamuomooueemu s\m I I + I + I I ouoaoe porous h\o I I I I I I I whom ooumuom eh I I I + I I I mums amoeba o\m + I I I I + scamsaoooamz no I I I I I .5535 ”Zoom m\o I I I I I I mnemmumhz ea\oa + I I + + + + I + + I + + + mnemenmuum oa\v I + + I I I I + + I mcrucmofleu w\a I I I I + I moeemcueocm oh I I I I I + pogo 338555 exo I I I I 23.3% 23 «\H + I muumeemms Hmeomm m\m I + I + I I I I I wamsemoouufiz e) I + I I £5380 upfi me I I I onooBfloo eh I + I I safiomosooopm m\m + + + + I + + + + enmseaasm :5 9mm no me me om mm em om me mm mm mm woe 353mm 8: mm em em .3 mm mm om om me mm em mm mm mm woe 363m; Tm o.m o.m Tm m.m mgr, sum o.m ~.m homeogfim scabs s s z z s z m z s 2 s z z s m a do mm am om mm mm mm mm mm mm Hm om ma we be we me * mmmu .mommo oouuoeou mamsofl>mum ca oeouocwm Amaveoo >cfi mo mmcflocem cemwuocwcm .NH manna 70 oa\h m\m m} m\o m\~ 3% m? m\v m\m mH\mH h\H a: a} m} m} v\o +++ +++ I+++I |I++l ++I++ +++ ++ +++ +++I + I+I+ + I+++++I + moflodmamoumfiwa mam goons I monouflom coflmmohmos magma mom. Home Hmonocbs I page + amiss + augflomg 6.88m HBanoaoBa + + coflmoumumm Hmong I poomoc unmom mummoum Hmfioz nomad: H9902 moflomemomhm + whose? memoouoq we ma #996 Aomofinoov NH 0.3mm. 71 discussed in this section. Three of the published cases were excluded from phenotypic comparison for reasons previously given (see literature review). The data available on the remaining 16 ranged from carplete to minimal. When reviewing these cases, it was often difficult to determine the normal features of each patient, and staterents made by several authors regarding an overall absence of malfonmations in their patients were not reassuring . Patients were scored normal , or lacking a feature , if it was specifically stated tlat an examination for the feature had been atterpted, if a specific anatomical area had been evaluated and found normal, or if the feature was mentioned in a corparison with other patients. Published photographs were in general not acceptable sources of data . Even with these precautions, biases could not be avoided. To help overcome this problem, authors were contacted by letter, and additional data was obtained on three cases (Van Dyke, Crandall, personal communication). A sumary of the findings in these 16 patients appears in Table 12. The results are compared with our cases in Table 13. There was good agreement on the range of phenotypic features in both groups. Data on birth weights, pregnancy duration , and parental ages were in close agreement, as were the frequencies of the most canton abnormali— ties. With the exception of a short philtrum, the same facial features were present in both groups. Limb anomalies were less frequent in the published cases. In particular, there were no previous reports of increased carrying angles, or proximally placed digits . The vertebral column was involved in both grorps; lordosis was seen in our cases, 72 Table 13. Comparison of findings in previously reported cases with those in cases I-V. Sex 6F/10M 3F/2M Maternal Age 35 (13) 34.6 (5) Paternal Age 38.5 (11) 35.2 (5) Full Term 8 / 9 4/ 5 Brachycepha 1y 1/ 4 0/5 Flat Occiput l/ 4 2/5 Microcephaly 2/ 9 0/5 Facial Asymmetry 1/2 2/ 5 Low Hairline 0/ 4 2/5 Antimongoloid S lant l/ 6 3/ 5 Enopthalmos 1/6 2/5 Epicanthus 4/10 1/5 Strabismus 10/14 3/5 Nystagmus 0/ 6 1/5 Short Philtrum 0/5 4/5 Malocclusion 2/ 6 1/5 lowset Bars 1/7 4/5 Rotated Bars 0/ 7 3/5 Arched Palate 1/7 2/5 Camptodactyly 1/6 1/5 Clinodactyly l/ 6 2/5 Proximal Thumbs 0/5 2/ 5 Webbing Toes 2 & 3 2/6 4/5 Carrying Angle 0/5 5/5 Short Stature 6/10 3/5 Scoliosis 2/ 8 0/5 lordosis O/ 4 2/5 Kyphosis 1/5 0/5 Hypospadius Us 0/ 2 Normal Menses 1/ l 3/ 3 Nontal Breasts l/l 2/ 3 Heart Defect l/7 0/5 Nental Retardation 15/ 15 5/5 Developrental Retardation 8/ 9 5/5 Hyperactivity 4/5 5/5 Austism 4/ 6 1/5 Hypotonia 9/11 4/5 Abnormal Gait 2/5 4/5 Toe Walking 0/3 3/5 Aggression 1/ 3 5/5 Seizures 8/ 9 4/5 Abnormal EEG 8 4/5 Dermatoglyphics 7/10 4/5 73 while scoliosis and kyphosis were described in the others. Only a single instance of a heart defect or urogenital anomaly was evident. The behavioral abnormalities in our patients were also reported in some of the previously described cases. Of particular interest was the diagrosis of autism in four cases. Mental retardation was the common denominator of both groups . Our patients were severely and pro- foundly retarded; examples of mild and moderate retardation were present in the published group. Convulsive disorders were cannon in do reported cases. The age of onset of seizures was earlier, and the frequency more erratic in the patients of Power at al., 1977, Watson and Gordon, 1974, Crandall et al., 1973, Centerwall and Morris, 1975. Two cases reportedly suffered grand mal seizures as early as age six months. A syndrome may be defined from a composite of both groups. However, the frequency of certain features may later be amended. Features to be expected in 80 to 100% of the patients are: mental retardation , gross develogrental retardation, hypotonia , and behavioral disorders (hyperactivity, autism, aggression). 60% to 80% of the cases can be expected to have strabismus, short stature, convulsive disorders, and nonspecific dermatoglyphic findings. From 20% to 60% should have mild facial dysrorphisms such as a flat occiput, epicanthus, antimongoloid slant, enoptralmos, short philtrum, and lowset ears. The same mmmber should possess limb anomalies such as an abnormal carrying angle, clinodactyly, proximally placed digits, and webbing between toes 2 and 3. It should be etphasized tlat the expression of these traits is generally mild. Vertebral anomalies including 74 scoliosis, kyphosis, and lordosis occur in approximately 25% of the patients. Abnormalities of tlne urogenital system or heart are very un- likely. Aside from strabismus and hypotonia, abnormal neurological signs may occur, but are infrequent and nonspecific. Contractures, tremor, absent and hyperactive reflexes were observed in isolated cases. The gait may or may not be abnormal. In at least two cases (Crandall, personal communication, and Case II), the patients‘ coordi- nation and dexterity were especially good during childhood. Radio- logical, hematological , and biochemical findings are generally un— renarkable. Virtually all patients were the products of full term pregnancies, and unco'rplicated deliveries. Birth weights were appro- priate for gestatioral age . Two instances of mosaicism with contrasting phenotypes were reported. The motrer of two cases described by Power at al. (1977) , was herself a 46/47 mosaic. Only a single tissue was sampled, but from her reproductive history, it is safe to assume that gonadal tissue was also involved. She did not present with any abnormalities clearly related to the extra chrorosone. The patient of Van Dyke et al. (1977) had an unusual 46/47/48 mosaicism, and was as severely affected as the other cases. It was more likely in his case that the normal cell line arose after conception. The inv dup (15) phenotype is relatively unique among recognized autosomal syndrcmes. It is only mildly dysrorphic , and best crarac- terized by mental and developmental retardation, seizures, and be- havioral disorders . '75 2c. Unresolved cases similar to inv dup(15). Phenotypically, case VI resembles the inv dup(15) syndraxe. He was born at full.temmm and.was inactive and hypotonic as an infant. Later examinations revealed an abnormal EEG, developmental retardation, hyperactivity, epicanthal folds, strabismus, rotated ears, clinodactyly, proximally placed thumbs, an increased carrying angle, webbing between toes 2 and 3, and abnormal dermatoglyphics. In addition, his growth rate has shown a gradual decline. Certain cases in the literature may have inv dup(15) or a modified form. Padfield et al. (1968) described a case of Rubinstein, Taybi syndrome that Simpson (1973) later reported with an extra bin satellited chromosome. The patient was the product of a full term pregnancy, with normal birth weight. Both parents were 39. She had an antimongoloid slant, epicanthus , strabismus , nystagmus , short philtrum, malocclusion, ear deformities, arched palate, broad thumbs and toes, seizures, toe walking, and profound mental retardation (Partington, personalIosmmmrkxujrmn. Simpson interpreted the error as a partial trisomy 14 with G banding. The original karyotypes left some doubt, and the phenotypic findings were not entirely consistent with proximal trisomy 14 (Simpson and Zellweger, 1972) . Three cases in category 1 of the proximal 15 trisomies share many features in common with the inv dup(15) patients, and have not received an exhaustive cytogenetic evaluation.(Webb et al., 1967, Magenis et al., 1972, BewardrPebbles et al., 1977. See Table l and appendix for further details.) . 76 2d. Comparison of proximal trisomy 15 with the inv dup(15) syndrome. Cytogenetic studies on the inv dup(15) rearrangerent failed to clarify the nature of the euchromatic error. A recorparison of proximal trisomy 15 patients to those with inv dup(15) was performed with the hope of clarifying this problem. The results (excluding cases 1, 2, and 4 from the proximal trisomy group) are given in Table 14. A clear phenotypic distinction between the proximal trisomy and inv dup(15) patients is apparent. Proximal trisomy 15 is associated with more physical dysrorphisms, but not with seizures arnd behavior dis“ turbances. This would seem to argue that the euchroratic errors are quantitatively different. Unfortunately, a number of reasonable objections can be raised against the significance of this comparison. The preponderance of physical malformations in the trisomy patients may be attributable to autosomal imbalances involving chronosones other than number 15, since most of these cases resulted from malsegv- regatirng familial translocations. Furthermore, the exclusion of cases 1, 2, and 4 is not fully warranted; they may actually represent "pure" proximal trisomies.9 Additional banding studies on cases I, II and IV are certainly called for. Phenotypic similarities between these patients and those with inv dup(15) suggest that both groups may have the same euchronatic imbalance. A clear deronstration of this imbalance in 9The term "pure" is used in reference to a karyotypic aberration involving a well defined segment of gag chrorosone only. "Pure" proximal trisomies are especially valuable in phenotype - karyotype coorelations. Since trere is no corplicating input from a second chronosore (as in a translocation) I phenotypic abnormalities can be attributed to the "pure" aberration without ambiguity. 77 Table 14. Conparison of phenotypic findings associated with proximal trisomy 15 and those in inv dup(15) syndrome. Partial Trisomy inv dup(15) (11) Cases 14V literature (16) Strabismus 6/11 3/5 10/14 Epicanthus l/ll l/5 4/10 Ehopthalmos 3/8 2/5 1/6 Hypertelorism 3/7 0 O Lowset Ears 7/11 4/5 1/7 Malformed Ears 4/7 1/5 0 malocclusion 3/8 l/5 2/6 Palate Anomaly 9/11 2/5 2/7 .Micrognathia 6/8 0 0 Chest Deformuty' 3/8 0 l Kyphosis 3/8 0 l/5 webbing of Toes 2 & 3 3/11 4/5 2/6 Genital Anomaly 3/8 0 1 Short Stature 6/11 3/5 6/10 Mental Retardation 10/10 5/5 15/15 Hyperactivity 0 5/5 4/5 Autism 0 l/S 4 Seizures 0/6 4/5 8/9 78 cases I, II and IV may help to resolve the structural ambiguity of inv dup(15) . 3a. Mechanisms in the origin of inv dup(15) . Data bearing upon the origin of inv dup(15) suggest a spontaneous meiotic rearrangerent and nondisjunction. An analysis of polymor- phisms revealed the following information on our patients (see Table 9) . Case Origin I Maternal meiotic or post-meiotic II Maternal meiotic III Maternal meiotic IV Inconclusive V Meiotic , parent unknown In previously reported cases only two were mosaics , and it was not or could not be determined when their normal cell lines arose. The discussions of Van Dyke et al. (1977) , and Schreck et al. (1977) also enphasized meiotic events. Five mecranisms possibly responsible for the rearrangerents are sumnarized in Figure 20. Mechanism I produces a dioentric inv dup (15) with identical proximal and distal polymorphism, and is inconsistent with seven previously reported patients and cases I-V. mechanism II produces a monocentric inv dup(15) with dissimilar proximal and distal polymorphism, and is consistent with the data. Mechanism III produces a dioentric inv dup(15) and is also consistent with the data. Mechanisms IV and V involve parental chronosore 15 inversion heterozygosity. Nbchanism 79 I. Sister strand reunion. [I II. Nonsister chromatid translocation. Y 9 III. U~type nonsister chronatid exchange. iii-iii IV . Paracentric inversion . 00) H M Figure 20. Five mechanisms in the origin of inv dup(15) . 80 IV requires careful consideration. The derivative, a dioentric inv dup(15) with asymmetrical polymorphisms, is consistent with the data. A parental paracentric inversion of 15qll A 15q15 would be difficult to detect with current metaphase banding techniques. Studies on tie parents of our patients, and those of Van Dyke et al. (1977) were noninformative. A prometaphase study of these individuals is highly desirable since discovery of such an inversion would indicate a higher recurrence risk. Mechanism V, pericentric inversion heterozygosity, would be accorpanied by a noticeable change in the arm ratio of the affected horolog. Such a chrorosore has not been observed in our data , nor reported previously . Mechanisms II, III, and IV are tie most probable, and require a nondisjunction at sore point in meiosis. The tleoretical segregation behavior of these rearrangements is diagrammed in Figures 21 and 22. In mechanism II, first and second division nondisjunctions pro- duce the same findings as mechanisms III and IV: a first division error will result in the inheritance of an inv dup(15) and a rormal 15 with non-identical proximal polymorphisms; a second division error will result in tie inheritance of an inv dup(15) and a rormal 15 with identical proximal polymorphisms . 10 Chromosore 15 and inv dup(15) polymorphisms from cases Iu-V (see Tables 6 and 7), and the patient of Pfieffer and Kessel (1976) can be compared with these predictions. If all six cases are presumed to be 10Interpretations of meiotic errors based on the use of chroro- soral polymorphisms only must take short arm crossing over into account. C'hiasra on acrocentric short arms are difficult to resolve, but are believed rare (Hulten and Lindsten, 1970) . 81 First division nondisjunction. Hi 7‘7 One gametocyte receives all chrorosore 15 material. The second receives none . 2) Second division disjunction and centroxeric deactivation. Two orientations on the spindle are possible. Alternative A is inconsist- ent with the data . Alternative B produces the appropriate gametes . Alternative A Alternative B 0'7? E Centroneric deacti- 2 vation at this point prevents bridging . Z 3) Result, a 24 + inv dup(15) gamete. Note that the proximal poly- morphisms of the inv dup(15) and the rormal 15 are not identical, and that the distal inv dup(15) polymorphism is identical to that of the inherited normal 15. W (Note that the chrorosores are single stranded at this stage, but are drawn double stranded for the sake of clarifying inv dup(15) .) Figure 21. First division nondisjunction and second division centro— meric deactivation of inv dup (15) derived from either a paracentric inversion, or a U—type exchange . 82 First division centromeric deactivation prevents bridging. FBI—9% we 2) Second division nondisjunction of the normal 15/ inv dup(15) dyad. 9 3) Result, a 24 + inv dup(15) gamete. Note that in this case, the proximal polymorphisms on the inv dup(15) and the normal 15 are identical. M (Note that the chromosomes are single stranded at this point, but are drawn double stranded to clarify inv dup(15) .) Figure 22 . First division centromeric deactivation and second division nondisjunction of inv dup(15) derived from either a paracentric inversion or a Uo-type exchange. 83 meiotic in origin, the following conclusions regarding the division of nondisjunction can be drawn: Case First Division Second Division Nondisjunction Nondisjunction I + II + III + IV + v + Pfieffer and Kessel + Five of the six cases apparently nondisjoined in the second meiotic division. If a dioentric structure is also assumed, then centromeric deactivation probably occurred in first division in five cases, and in second division in one case. Studies on nondisjunction in Down syndrome have deronstrated its occurrence in both divisions, and both parents (Mikkelson et al., 1976, Wagenbichler et al. , 1976) . A relationship between advanced parental age and an increased likelihood of primary nondisjunction is well established in man. (Lilienfield and Bernesch, 1969, Penrose and Smitln, 1966) . The data for inv dup(15) also suggest that the risk for offspring with this abnormality increases with parental age. The mean maternal age in 18 cases was 34.8; the mean paternal age in 16 cases was 37.5. Although the timing of events in meiosis can be predicted from the theoretical behavior of inv dup (15) , there is no evidence favoring one mechanism of rearrangenent over the others. An additional corplicaa- tion must also be recognized. Two cases probably underwent further structural modification during , or following, the initial rearrange- ment. In tre patient of Centerwall and Morris (1975) , and in one patient of Schreck et al. (1977) , proximal satellites were inexplicably 84 deleted. These variants suggest that the mechanism producing some inv dup (15) 's is more conplex than those previously reviewed. The nature of this alternative mechanism is not apparent in the data. 3b. Additional etiological considerations. Reproductive histories were incompletely reported in the litera- ture . Data for the calculation of spontaneous abortion frequencies in families where consanguinity or mosaicism were not present, were obtained from cases II-V, and the reports of Crandall et al. (1973) , Centerwall and Morris (1975) , and Pfieffer and Kessel (1976) . A total of 41 pregnancies and 34 live births gave an abortion frequency of .17, a figure consistent with the expected value, .15. The mosaic described by Power et al. (1977) had a total of two affected and three rormal children, a first trimester spontaneous abortion, and a second trimester spontaneous abortion. Assuming that all of her gonadal tissue contained the inv dup(15) , approximately one half of her pregnancies were at risk due to secondary nondisjunction. The retaining families were ascertained through a single affected child. One patient (Kakati and Sinla, 1973) had a hyperactive sib, but no details were available. The patient of Van Dyke et al. (1977) had two sibs in special education classes. The parents were first cousins. The only sib of patient RD (Crandall et al., 1973) died of multiple congenital anonalies including absent thumbs and spina bifida . The remaining family histories were unrenarkable. No teratogenic exposure prior to conception was evident for any of our patients or those reviewed in the literature. Birth dates were 85 available in only six cases, and were insufficient to suggest any seasonal clustering. In parity, patients were always last, or second to the last, reflected in a high mean parental age. First cousin consanguinity was reported in the parents of two cases (Van Dyke et al., 1977, Watson and Gordon, 1974) . The nationality of the con- sanguineous parents were Pakistani and Palestinian. In the remaining cases, racial background, where reported, was caucasian, except for case V, a black American fenale. 3c. Etiological conclusions. It is concluded tl'at inv dup(15) arises sporadically, is more likely in offspring of older parents, and cannot as yet be associated with a specific recurrence risk. A cormon mectanism of origin is likely, given the consistency of the rearrangerent. Prophase banding studies are clearly indicated because of the unsolved question of paracentric inversion heterozygosity . The frequency of reported cases may suggest that an inverted variant 15 is segregating in certain populations, and may carry with it a definable risk for offspring af- fected with inv dup(15) . m Extra bisatellited acrocentric chronosones were detected in six unrelated patients with mental retardation and minimal sonatic ab- normalities. In five of the six, the supernurerary was larger than a number 22, and had GIG, RHG, and $0 patterns similar to proximal 15q. Proximal and distal CBG bands were deronstrated, indicating a euchro- matic segment bordered on either end by material derived from an 86 acrocentric short arm. A dioentric structure was suggested by these findings, but only a single primary constriction was evident. Anti, SI—methylcytidine banding identified chrorosome 15 as the origin of tie CBG positive material. These results matched those of chrono- sone 15 derivatives described as inv dup(15) (pter - ql:pl or ql— pter) by Schreck et al. (1977) . Alternative structures for inv dup(15) can be proposed. The simplest interpretation is t(15;15) (pll;q15) , a proximal long arm trisomy acconpanied by a partial short arm tetrasomy. More complex interpretations involving two centroreres and a long arm tetrasomy, such as tdic(15;15) (ql4;q14) , can also be considered. Current meta- phase techniques are unable to distinguish between these alternatives . Data bearing upon the origin of inv dup(15) were obtained from CBG and QFQ polymorphism studies. Family studies in cases Iw-III were consistent with the mums-methylcytidine data. In cases II=-III, QFQ inv dup(15) polymorphism indicated a maternal meiotic origin. Data on cases IV and V were more limnited, although no inconsistencies with tlne anti~5-methylcytidine results were noted. QFQ polymorphisms in case V supported a meiotic origin. Inv dup(15) is likely to have arisen via tre meiotic mecl'anisms of translocation, U-type exchange, or parental paracentric inversion hyeterozygosity, followed by a nondisjunction. Proximal and distal QFQ polymorphism asymmetry in all five patients ruled out an origin via sister chroratid exchange. An analysis of the theoretical segre- gation behavior of the derivative suggested the occurrence of second division nondisjunction in four of our cases, and one in the litera- ture . 87 The extra chromosome in our sixth patient was sraller than inv dup(15) . CBG studies failed to denonstrate a distal l'eterochromatic band. GI'G, QFQ, and RHG results were similar to inv dup(15); antiv-S- methylcytidine banding confirmed a chronosone 15 origin. The abber— ration was interpreted as t(15;15) (pll;ql4 or 15) . Polymorphism stud:- ies were non-informative. Clinical studies on our cases suggested an association between inv dup(15) and a distinct syndrore. As many as 19 patients with this aberration have appeared in the literature . However , confusion over the identity of the derivative, and the isolated nature of the reports, prevented previous recognition of this syndrone . Comparison of our patients and 16 of the 19 in the literature revealed a consistent pattern of phenotypic abnormalities. Virtually all patients had mental and developrental retardation , hypotonia , and behavioral disturbances . 60% to 80% had seizures, short stature, and nonspecific dermatoglyphic abnormalities. 20% to 40% had mild facial and limb dysnorphisms, and vertebral anomalies. A de rovo meiotic origin was indicated in almost all cases, and parental ages were distinctly elevated. Available data suggests a sporadic occurrence , and are insufficient to propose a specific recurrence risk. Proretaphase banding studies are suggested, both to better define the structure of inv dup(15) , and to explore tl'e possibility of parental paracentric inversion hetero- zygosity. APPENDICES APPENDIX A 88 APPENDIX A Case Summaries of Previously Reported Cases Category 1 Case 1. Webb et al. (1967). Partial D trisomy was reported in a profoundly retarded 8 year old girl. The supernumerary was described as 65% of the size of a normal D group, with a satellited short arm, and a "negatively hetero- pycnotic" area on the distal end of the long arm. Autoradiography was consistent with chronosome 15. Mosaicisn was denonstrated in blood, marrow, and skin. The patient was born to a 46 year old father and a 38 year old mother. The family history was negative. The pregnancy was initially threatened by miscarriage. Birth weight was 3040 gm. Evaluation at 8 years revealed profound mental retardation, hyperac- tivity, epicanthal folds , mild microcephaly, and normal dermatoglyphics . The mother's pregnancy history included 7 liveborn children, and two first trimester spontaneous abortions. Case 2. Magenis et al. (1972) . An extra 15q- chrorosore with an apparent breakpoint of 15q21 was identified by G and Q banding in a 12 year old girl. The patient was born to a 30 year old mother, was 1 week pretature, and weighed 6 lb. 6 oz. She was lethargic and inactive from birth, and difficult to feed. Developmental retardation was evident. At age 12 , her height arnd weight were less than 10th percentile. She was profoundly 89 retarded, had epicanthal folds , a wide nasal bridge , strabismus , anti- mongoloid slant, large mouth, widely spaced teeth, full lips , retro- cessed large ears, mild kyphosis, spindle sraped fingers, brachy- dactyly of the 5th fingers, and cubitus valgus. Additional findings are available in Centerwall and Harris (1975) . Case 3. Mankinen et a1. (1976) . Proximal trisomy 15pter ~+ qlS was identified by Q, R, G, and C banding in a 5.75 year old ferale. The patient was born to a 36 year old father and a gravida 5, para 4, 34 year old mother. Little fetal activity was noted during the pregnancy. The birth was premature; the patient weighed 2100 gm. and the umbilical cord was wrapped once around the neck. Noted at birth were micrognathia, cleft palate, a hooked nose, and lowset ears. Cardionegaly, absence of sucking and rooting reflexes, generalized hypotonia, and 50th percentile values for reight and weight were mentioned in the first year. At 5.75 years, head circumference, height, and weight were all below the 3rd percentile. Additional findings were prominent philtrum, small mouth, irregular dentition, single palmar creases, clinodactyly, decreased subcutaneous tissue, and severe mental retardation. Case 4. Howard—Peebles and Yarbrough (1977) . Proximal trisomy 15pter ~> q21 or 22 was identified by G banding in a 10 year old girl. The patient was born to a 31 year old father and a 30 year old mother. There was a negative family history, no evidence of pregnancy wastage, and 2 rormal sibs. The patient' 3 birth was 5 weeks premature, and she weighed 1956 gm. Walking occurred at 90 15-l6 months. She had a severe language delay, poor gross and fine motor control , hyperactivity, and moderate mental retardation . Physical examination at age 10 revealed strabismus, slight hyper— telorism, a slightly high arched palate, squared off feet, and bilateral Clinodactyly. Her weight was 58th percentile, head circumference 50th percentile, and height 3rd percentile. Category 2 Case 5. Rethore et al. (1973) . Proximal trisomy lS/partial monosony 21 was described in a 14.75 year old ferale due to malsegregation of a maternal t(15;21) (q13;q22) . The patient was the product of a rormal pregnancy and weighed 2600 gm. at birth. Thrombocytopenia occurred at the age of 4 but later regressed. Eb q12 -) pter) . The authors proposed that the secornd small submeta- centric marker arose mitotically from the first as the result of a bridge-breakage- fusion cycle initiated by functional dioentric activity in the first marker. Q and C band polymorphisms, as well as anti-5* methylcytidine banding, were consistent with a chromosome 15 origin for both ends of the larger supernumerary. The patient had 11 sibs, 2 of whom were in special education classes. The parents were first cousins. The mother was 38 at the time of the patient's birth. At age 7, he was described as hyperactive, severely retarded, with a normal physical appearance except for strabismus and a maxillary over~ bite. An EEG showed a diffuse disturbance of cerebral function. Urine arnd amino acid screens were normal. Cases 30, 31, and 32. Schreck et al. (1977). In addition to the 3 patients previously mentiored, 3 additioral cases were briefly described in this report. All were identified as having an inv dup(15) . Case 30, a male, was profoundly retarded, hypotonic, had facial asymmetry, and hypospadius. Parental ages at birth were M = 42, P = 45. Case 31, a male, was profoundly retarded with a convulsive disorder and slight scoliosis . Parental ages were M = 36, P = 42. Case 32, a female, was mildly retarded, had a perv- sonality disorder, and strabismus. Parental ages were M = 34, P = 53. Case 33. Jacobs et al. (1978) . The authors in this case did not attempt to identify the extra chromosome, but presented the results of G and C banding uninterpreted. 103 The patient was a 29 year old female, with four other sibs. Parental ages at birth were M = 35, P = 32. The patient was the product of a normal pregnancy and weighed 6 lb. 6 oz. Her development was described as normal until the age of 1 when she developed acute septic spiral meningitis. She regressed to an infantile state, losing the ability to walk and talk. She was institutionalized in 1957. In 1965, her IQ was 20. Her clinical findings include hip luxation, seizures, hirsutism, small hands held in a silver fork attitude, tapered fingers with some clubbing, tapered toes, hypotonia, hyporeflexia, and spastic- ity. APPENDIX B 104 APPENDIX B Phenotypic Checklist Supplied to Previous Investigators Case Age Birth weight Duration of pregnancy Age of mother at birth Age of father at birth PHYSICAL FINDINGS (At anytime in patient's history) HEAD Yes No Suggested Not Evaluated Brachycephaly Dolioocgphaly Reduced Bitemporal Diameter Flat Occiput Microcepl'aly Other: FACIES low Posterior Hairline AntimonLoloid Slant Emnopthalmos Epicanthal Folds Wlorism Yes 105 No Suggested Not Evaluated Strabismus Nystagmus Flat Nasal Bridge Short Philtrum Thickened Lips Pregnathism Downturned Mouth Malocclusion Lowset Ears Deformed Ears Rotated Ears Other: EXTREMITIES Increased Carrying Angle camptodactyly Clinodactyly Proximally Placed Thumbs Itmmer Toes Syndactylyyof Toes 2 and 3 Club Foot Ckher: TRUNK Short Stature Yes 106 No Suggested Not Evaluated Scoliosis lordosis Kyphosis Sacral Dimples Hmospadius Cryptorchidism Normal Nenses Normal Breasts Heart Defect Other: NEUROMISICAL Mental Retardation (degree) Develogrental Retardation Hyperactivity Autistic Behavior Aggressive Behavior Hypotonia Poor Sucking Reflex Abnormal Speech Abnormal Gait (not attributed to drugs or brain damage due to seizures) Toe Walking Other: 107 History of Seizures? Frequency? Abnormal EEG? (brief interpretation) Anticonvul sants? (describe) Missing or Abnormal Reflexes? (describe) Feeding or Digestive Problems? (describe) Dermatoglyphic Abnormalities? (describe) current Status (change in EEG findings, etc.) Other: APPENDIX C 108 APPENDIX C Analysis of Familial Polymorphisms - Cases I—V Case I and Parents (DD) A B C D E F Possible rearrangements 13 P l-l S lo-lS =- .. mat t(14;15) p 2,-1 L - t(15;15) M 2'1 L - - t(15;22) M 2-1 L 2=—1L .. .. pat t(15;22) 14 P 1~1 s - - mitotic t(l4;15) P lv-l S 1-1S - t (15 ; 15) M la-l S - ... M 1-1 L lv-lL + l 15 P 1-2 L lo-2L a- + P 1-2 L - + Darker: M 1-2 L - + p = 1-1L M 1-1 L l-lL + '- q = 1-2L 21 P 1~3 S 1’33 .. - P 1-1 S M l-l S 1--lS - .. M lwl S 22 P 2-1 L 2°-1L — - P l~l L + - M 2—1 L 2-»lL - - M 1-1 L + l A = parental chranosares B = QFQ scores for parental chrorosores. First digit for sl'ort arm, second digit for satellites C = CBG score for parental chromosomes D = Normal Acrocentrics in Proband E = +, similar to marker short arm polymorphisms, -, not similar F = +, similar to marker long arm polymorphisms, .., not similar 109 Case II and parents (CL) Possible rearrangements mat t(14;15) t(15;15) pat None LLLS P 2'1 M. 1~1 M. 2'1 13 P 2’1 .Mitotic None l~2L l-lS 1-1S 1-28 5885 P 1,1 M. 1’2 M. 1'1 21 P l~l E S .1 . . 1. 1i carucocc 1.1.9.11 _ . a _ 7.111111 p.p.MHMH 2 2 Case III and parents (NE) mat t(l4;15) t(15:15) t(15;21) t(15,22) pat None Mitotic None . + + + l-lL 1~1L .L.L.L.L P 1-1 M. 1~1 M. 1’1 14 P 1'3 Marker: Turururu P 1’1 M. 1'2 M. 1'1 15 P 1-1 p = 1-lL L 2 . 1.. p q .p_p ...... S S 3 l _ a 11 11 SSLS 3111 yap, 1111 D.D.MHMH l 2 A. B 22 P 2’2 P l’l .M 1,1 M. 1-1 Case IV (RP) 13 2'1 2~l 14 1'1 1-2 15 1-1 1P1 21 1-1 1.1 22 2'1 1’1 Case V (EL) 13 1’1 2-1 14 1’1 1’1 15 1'1 1'1 21 1'1 1'1 22 1—1 1’1 A: B: C: D: IT'UJUJL" O 1'15 1'18 Acrocentric chromtmxmmes QFQ scores of acrocentric chratosomes. First digit for short arm, second digit for satellites +, similar to marker short armnpolymorphisms, ~, not similar +, similar to marker long anm.polymorphisms, ,, not similar 110 Possible rearrangements Parental ? Mitotic t(14;14) t(l4;15) t(14;21) t(14;22) Parental ? .Mitotic None Marker: p = 1-2 q - 1-1 Case VI (TM) .A 13 14 15 21 22 S S'U'U B S'U'U 3 B'U'U a B'U'U B B'U'U B 2'1 2’1 2-1 2~1 1’3 1'2 1-2 1’2 1~3 1‘2 1’2 1~2 1'1 1~1 1’2 1’1 1'1 1'2 1'3 2’1 C) Ull'DUDUJ t‘t‘t‘t‘ t‘f‘t‘t‘ mmmm 0')me 2~lS 2-1S 1~2L 1w2L 1*2L 1'2L 1’15 1'15 1~2L 1-3S t6 3111 + + + 1 + + + l iii 1 Ii+1 I i + n u + + + I + + + i n + i 111 Possible rearrangements Mat t(14;l4) t(14715) t(14;21) t(15;21) Pat t(14:15) t(l4;22) t(15;22) Mitotic t(14;l4) t(l4;15) t(l4;22) t(15;15) t(15;22) p = 1'2L q = 1-2 112 LIST OF REFERENCES Abbo, G. and Zellweger, H. The syndrome of the metacentric micro~ chromosome. Helv. Paediat. Acta 25:83-94, 1970. Archidiacono, N., Rocchi, M., de Vonderweid, U. and Filippi, G. t(9/22) with centric fission and NOR translocation leading to a case of pure 9p trisomy in the offspring. Hum. Genet. 40: 325-331, 1978. Aula, P., leisti, J. and von Kuskull, H. Partial trisomy 21. Clin. Genet. 4:241-251, 1973. Balicek, P., Zizka, J. and Lichy, J. An isochromosome of the short arms of the no. 18 chromosome in a mentally retarded girl. Clin. Genet. 9:192-196, 1976. Bannister, D.L., and Engle, E. A Gw-like trisomy with a major 15 proximal supernumerary comporent derived from a D/E balanced maternal interchange. J. Pediat. 916-917, 1975. Benn, P.A. Specific chromosare aberrations in senescent fibroblast cell lines derived from human embryos. Amer. J. Hum. Genet. 28:465-473, 1976. Bloom, G.E. and Gerald, P.S. localization of genes on chrarosare 13: analysis of two kindreds. Amer. J. Hum. Genet. 20:495—511, 1968. Bloom, A.D. Induced chrarosaral aberrations in man. Advances in Huran Genetics pp. 99-172, 1972. Brandham, P.B. Stabilized breakage of a duplication chromosane seg- ment i Aloe. Chronosata 51:369~378, 1975. Breg, W.R., Miller, O.J., Miller, D.A. and Allderdice, P.W. Distinc- tive fluorescence of quinacrine-labelled hunan G group chromo- sares. Nature New Bio. 231:276a-277, 1971. Breg, W.R., Schreck, R.R..and Miller, O.J. Familial partial trisomy 15: identification of a deleted no. 15 confirmed by anti-45:- methylcytodine antibody banding. Amer. J. Hum. Genet. 29:17A, 1974. 113 Bucher, W., Parker, C.E., Crandall, B. and Alfi, O.S. Partial tri- somy of chromosme 15. lancet 1:1250, 1973. Caspersson, T., Zech, L. and Johansson, C. Analysis of human chroro- some set by aid of DNA-binding fluorescent agents. 92- Cell 32° 62:490-492, 1970. Castel, Y., Riviere, D., Boucly, J—Y. and Toudic, L. Trisamie 15q partielle par translocation maternelle t(7 :15) (q35;q14) . fl. Genet. 19:75-79, 1976. Centerwall, W.R. and Morris, J.P. Partial D15 trisomy. Hum. Hered. 25:442-452, 1975. Chicago Conference. Standardization in Human Cytogenetics. Birth Defects: Original Art. Series II 2, The National Foundation - March of Dimes, New York, 1966. Christensen, K.R. and Nielsen, J. Partial XYY syndrare. Hum. Genet. 12:3235-329, 1971. Cohen, M.M., MacGillivray, M.H., Capraro, V.J. and Aceto, T.A. Human dioentric Y chromosomes. J. bed. Genet. 10:74—79, 1973. Condron, C.J., Cantrell, R.J., Kaufman, R.L., Brown, S.B. and Warren, R.J. The supernumerary isochrcmosome 18 syndrome. Birth Defects: Original Art. Series X 10, pp. 36—-42, 1974. Crandall,BF,1~4uller,HMandBass,HN Partialtrisomyof chrunosare number 15 identified by trypsin—giemsa banding. Amer. J. Ment. Def. 77: 571—578, 1973. Dallapiccola, B., Mastroiacovo, P. and Gandini, E. Centric fission of chranosome 4 in the mother of two patients with trisomy 4p. Hum. Genet. 31:121v-125, 1976. de Grouchy, J. and Turleau, C. Clinical; Atlas of Huran Chromosanes. John Wiley arnd Sons, New York, 1977. de Gutierrez, A.C., Salamanca, F., Lisker, R. and Segovia, A. Supernurerary bisatellited chrorosare in a family ascertained through a patient with Stmrge—Weber syndrome. Ann. Genet. 18:45-49, 1975. Disteclne, C., Hagemeijer, A., Frederic, J. and Progneaux, D. An abnormal large human chrarosome identified as an end to end fusion of two X's by combined results of the new banding techniques and microdensitatetry. Clin. Genet. 3:388—395, 1972. 114 ENans, H.J. Chronosone aberrations induced by ionizing radiations. Inter. Rev. Cytol. 13:221, 1962. Friedrich, U. and Nielsen, J. Bisatellited extra small metacentric chrorosores in newborns. Clin. Genet. 6:23v-31, 1974. Fugimoto, A., waner, J.W. Ebbin, A.J., Kahlstrom, E.J. and Wilson, M.G. Inherited partial duplication of chronosore no. 15. J. Med. Genet. 11:287v-29l, 1974. Garlinger, P., McGeary, S.A. and Magenis, E. Partial trisomy 22: a recognizable syndrome. Clin. Geret. 12:9v-l6, 1977. Gerald, P.S., and Walzer, S. Chrorosore studies of rormal newborn infants. Human POpulation Cytogenetics, Edinburgh University Press, Edinburgh, pp. 143-151, 1970. German, J. Genes which increase chromosotal instability in somatic cells and predispose to cancer. Progress in Medical Genetics VIII:6l-102, 1972. Hagereijer, A. and Smit, E.M.E. Partial trisomy 21. Hum. Genet. 38:15-23, 1977. Hamerton, J.L., Canning, N., Ray, M. and Smith, S. A cytogenetic survey of 14,069 newborn infants. 1. Incidence of chrorosote abnormalities. Clin. Genet. 8:223-243, 1975. Hansen, S. A case of centric fission in man. Hunangenetik 26: 257«-259, 1975. Hassold, T. Fingerprint Patterns in Idiopathic Mental Retardation. Thesis, Michigan State University, 1977. Hoefnagel, D., Benirschke, K., Mavalwala, J. and Brownhill, L. Un- usual dermatoglyphic patterns associated with chrorosonal abnormalities. J. Ment. Defic. Res. 7:90-101, 1963. Hook E.B. Exclusion of chrorosomal mosaicism: tables of 90%, 95%, and 99% confidence limits and comments on use. Amer. J. Hum. Genet. 29:94-97, 1977. Howardo-Peebles, P.N. and Yarbough, K. Partial trisomy of chromosore 15. Amer. J. Ment. Def. 81:606—609, 1977. Hsu, L.Y.F., Shapiro, L.R., Gertner, M., Lieber, E. and Hirschhorn, K. Trisomy 22: a clinical entity. J. Pediat. 79:12,.19, 1971. Hsu, L.Y.F. and Hirschhorn, K. Trisomy 22 syndrome and the Cat-Eye . Newgnrorosomal Syndromes, Academic Press, New York, pp. 339-368, 1977. Hsu, T.C. Mammalian Chromsore Newsletter 17:1, 1976. 115 Hulten, M. Chiasna distribution at diakinesis in the normal human male. Hereditas 76:55-78, 1974. Hulten, M. and Lindsten, J. The behavior of structural aberrations at male meiosis. Information from man. Human Population Cyto- genetics. Edinburgh University Press, Edinburgh, pp. 23-61, 1970. Jacobs, P.A. Frankiewicz, P. and Law, P. Incidence and mutation rates of structural rearrangerents of He autosones in man. Ann. Hum. Genet. 35:301—319, 1972. Jacobs, P.A. Correlation between euploid‘ structural chrorosore rev- arrangerents and mental subnormality in humans. Nature (lond) 249:164«-165, 1974. Jones, C.H. arnd Brurptom, R.J. Sister and non—sister chromatid Uo-type exchanges in rye meiosis. Chronosona 33:115-128, 1971. Kakati, S. and Sinha, A.K. Induction of distinctive chrorosomal bands in selected human subjects with D, G. and Y chronosomal arnotalies. Hum. Hered. 23:313-330, 1973. lauritsen, J .G. Genetic Aspects of Spontaneous Abortion. Aarhus Universitet , T977 . lejeune, J., Gautier, M. and Turpin, R. Etude des chrorosores somatiques de neuf enfants mongoliens. C.R. Acad. Sci. 248: 1721~l722, 1959. Lilienfeld, A.M. and Benesch, C.H. Epidemiology of angolism. The Johns Hopkins Press, Baltimore, 1969. Lindenbaum, R.H. and Bobrow, M. Reciprocal translocations in man. 3 : 1 meiotic disjunction resulting in a 47 or 45 chronosone offspring. J. Med. Genet. 12:29—43, 1975. magenis, R.E., Overton, K.M., Reiss, J.A., McFarlane, J.P. and Hect, F. Partial trisomy 15. lancet 2:1365—1366, 1972. Mankinen, C.B., Holt, J.G. and Sears, J.W. Partial trisomy 15 in a young girl. Clin. Geret. 10:27-32, 1976. Matter, K. and Stone, L.H.A. The effect of x radiation upon somatic chronosones. J. Genet. 28:1-24, 1933. NbClintock, B. Chrorosore organization and genic expression . Cold Spring Harbor Symp. Quant. Bio. 16:13-47, 1951. Mikkelsen, M., Hallberg, A. and Poulsen, H. maternal and paternal origin of extra chrotosone in trisomy 21. Hum. Genet. 32:17—21, 1976. 116 Miller, O.J., Schnedl, W., Allen, J. and Erlandger, B.F. 5-methyls- cytosine localized in mammalian constitutive heterochromatin. Nature 251:636—637, 1974. Nborhead, P.S., Nowell, P.C., Mellman, W.J., Battips, D.M. and Hungerford, D.A. Chrorosore preparations of leukocytes cultured hon human peripheral blood. Exp. Cell Research 20:613'616, 1960. Nakagone, Y., Teramura, F., Kataoka, K. and Hosono, 15‘. Mental retardation, malformation syndrore and partial 7p mornosomy. Clin. Genet. 9:621--624, 1976. Nielsen, J., Hreidarsson, A.B., Berggreen, S., Ried, B., Tsuboi, T. and Saldana-Gracia, P. A mentally retarded male with karyotype 47, XY, + mar = ?i(18p). Ann. Genet. 17:129—133, 1974. Nielsen, J., Friedrich, U. and Tsuboi, T. Father and son with karyo- otype 47, XY, ? qu. Hum. Genet. 11:247—252, 1971. Nieburh, E . Dicentric and monocentric Rbbertsonian translocations in man. Hurangenetik 16:217r—226, 1972. Noel, B., Quack, B. and Rethore, M.O. Partial deletions and trisomies of chrorosore 13; mapping of bands associated with particular malformations. Clin. Genet. 9:593—602, 1976. Ogata, K., Iinuna, K., Kamimura, K., lbrinaga, F. and Kato, J. A case report of a presumptive + i(18p) associated with serum IgA deficiency. Clin. Genet. 11:184-188, 1977. Padfield, C.J., Partington, M.W. and Simpson, N.E. The Rubinstein- Taybi syndrome. Arch. Diseases Child. 43: 1968. Pallister, P.D., Patau, K., Inhorn, S.L. and Opitz, J.M. A woran with multiple congenital anoral ies , mental retardation, and mosaicism for an unusual translocation chrorosore t(6;19) . Clin. Genet. 5:188’195, 1974. Palmer, C.G.,.Conneally, P.M. and Christian, J.C. Ti‘anslocations of D. chrorosomes in two families: t(13q14q) and t(13q14q) + (13p14p). J. red. Geet. 6:166-173, 1969. ' Palutke, W., Chen, H., Woolley, P., Espiritu, C., Vogel, H.L, Gohle, N. and Tyrkus, M. An extra stall metacentric chronosore identi- fied as a deleted chrorosome 17. Clin. Genet. 9:454—458, 1976. Parker, C.E. and Alfi, O.S. Partial trisomy of chronosore lS. lancet 1:1073, 1972. Penrose, L.S. and Smith, G.F. Dawn's Anoraly. Little, Brown, and Co., Boston, pp. 162—163, 1966. 117 Pfeiffer, R.A. and Kessel, E. Partial trisomy 15q1. Hum. Genet. 33:77-83, 1976. Power, M.M., Barry, R.G., Cannon, D.E. and Masterson, J.G. Familial partial trisomy 15. Arm. Genet. 20:159-165, 1977. Rasmussen, K., Nielsen, J., Sillesen, I., Brask, B.H. arnd Saldana-Garcia, P. A bisatellited marker chronosore in a mentally retarded girl with infantile autism. Hereditas 82:37-42, 1976. Rethore, M.O., Dutrillaux, B. and lejeune, J. Translocation 46, XX, t(15;21) (q13,q22,l) chez 1a mere de deux enfants atteints de trisomie 15 et de monosomie 21 partielles. Ann. Geret. 16:271- 275, 1973. Roberts, S.H., Howell, R.T., Laurence, K.M. and Heathcote, M.E. Stable dioentric autosore, tdic(s;22) (P23:p13) in a mentally retarded girl. J. Nbd. Genet. 14:66-68, 1977. Salamanca, F. and Armendares, S. C-bands in human metaphase chromo- sores treated by Ba(OH)2. Ann. Genet. 17:135-137, 1974. Sandberg, A.A., Koeph, G.F., Ishihara, T. and Hauschka, T.S. An XYY human male. lancet 2:488-489, 1961. Schachenmann, G., Schmid, W., Fraccaro, M., Mannili, A., Tiepolo, L., Perona, G.P. and Sartori, E. Chrorosones in coloboma and anal atresia. lancet 2:290, 1965. Schinzel, A., Hayashi, K. and Schmid, W. Further delineation of the clinical picture of trisomy for the distal segment of chrorosore 13. Hum. Genet. 32:1-12, 1976. Schreck, R.R., Breg, W.R., Erlanger, B.F. and Miller, O.J. Preferen- tial derivation of abnormal human G-like chrorosores from chronosore 15. Hum. Genet. 36:1-12, 1977. Sears, E.R. and Camera, A. A transmissible dioentric chrorosore. Genetics 37:125-135, 1952. Simpson, J. and Zellweger, H. Partial trisomy 14g- and parental translocation of no. 14 chromosone. Report of a case and review of the literature. J. Med. Genet. 14:124-127, 1977. Simpson, N.B. The Rubinstein-Taybi syndrone: chronosonal studies. Amer. J. Hum. Genet. 25:230-236, 1973. Sinha, A.K., Pathak, S. and Nora, J.J. A human family suggesting evidence for centric fission and stability of a teleocentric chrorosole. Hum. Hered. 22:423-429, 1972. Soudek, D., McCreary, B.D. and laraya, P. Two kindreds with acces- sory bisatellited chrotosone. Ann. Geret. 16:101-107, 1973. 118 Soudek, D. and Sroka, H. C—bands in seven cases of accessory small chromosores. Clin. Genet. 12:285-289, 1977. Speed, R.M., Johnston, A.W. and Evans, H.J. Chromosone survey of total population of mentally subnormal in north-east of Scotland. J. Med. Genet. 13:295-306, 1976. Sun, N.C., Chu, B.H.Y. and Chang, C.C. Staining netted for the banding patterns of hutan mitotic chrorosones. Caryologia 27: 315-324, 1974. Tangheroni, W. , Cao, A. and Furbetta, M. Multiple anoralies asso- ciated with an extra stall metacentric chronosone: modified giemsa staining results. Hum. Genet. 18:291-295, 1973. Taylor, K.M., Wolfinger, H.L., Brown, M.G. and Chadwick, D.L. Origin of a stall metacentric chrorosore: familial and cytogenetic evidence. Clin. Geret. 8:364—369, 1975. Tooney, K.R., thandas, T., Leisti, J., Szalay, G. and Kaback, M.M. Furtter delineation of the supernumerary chronosote in ttne Cat- Eye syndrome. Clin. Genet. 12:275-284, 1977. Turleau, C., de Grouchy, J., Chavin-Colin, F. and Ibubin. M. Trisomie 15q distale. Ann. Genet. 20:214-215, 1977. Therman, B., Sarto, G.E. and Patau, K. Apparently isodicentric but functionally monocentric X chrorosone in man. Amer. J. Hum. Genet. 26:83-92, 1974. Valenta, L.J., Higgins, J.V. and Holzman, G.B. Ovarian dysgenesis due to 45 X,0/46 dic(x) mosaicism. J. Clin. Endo. Metabolism 45: 702-706, 1977. Van Dyke, D.L., Weiss, L., Logan, M. and Pai, G.S. T'te origin and behavior of two isodicentric bisatellited chronosomes. Amer. J. m. Gene . 29:294-300, 1977. Wagenbichler, P., Killian, W., Rett, A. and Schnedl, W. Origin of tte extra chronosore no. 21 in Down syndrore. Hum. Genet. 32: 13-16, 1976. Wahrman, J., Goitein, R., Richler, C., Goldman, B., Akstein, E. and Chaki, R. The mongoloid phenotype in man is due to trisomy of the distal pale G-band of chronosone 21. Chromosores Today 5: 241-248, 1976. Warburton, D., Henderson, A.S., Shapiro, L.R. and Hsu, L.Y.F. A stable human dioentric chrorosore, t dic (12:14) (913;pl3) in- cluding an intercalary satellite region between centroneres. Amer. J. Hum. Geret. 25:439—445, 1973. 119 Watson, E.J. and Gordon, R.R. A case of partial trisomy 15. J. Med. Genet. 11:400-402, 1974. Webb, G.C., Garson, D.M., Robson, M.K. and Pitt, 0.8. A partial D— trisomy/normal mosaic female. J. Med. Genet. 8:522-527, 1971. Williams, J.D., Summitt, R.L., Martens, P.R. and Kimbrell, R.A. Familial Down syndrone due to t(10;21) translocation: evidence that the Down phenotype is related to trisomy of a specific segment of chronosone 21. Amer. J. Hum. Genet. 27:487-485, 1975. Wilroy, R.S., Summitt, RmL., Martens, P. and Gooch, WhM; Partial mornosomy and partial trisomy for different segments of chrorosore 13 in several individuals of. the same family. Ann. Genet. 20: 237-242, 1977. Wisniewski, L. and Higgins, J .V. Nbsaicism presunably related to a Y/ 6 translocation in a boy with multiple congenital abnormali- ties. J. Med. Genet. 14:387, 1977. Wisniewski, L., Politis, G. and Higgins, J .V. Partial tetrasomy 9 in a liveborn infant. Clin. Genet. (in press). Wurster-Hill, D.H. and Hoefnagel, D. Banding identification of partial trisomy 15 and of 8/21 translocation. J. Ment. Def. Res. 18: 139-144, 1974. Yunis, J .J . and Hook, E.B. Deoxyribonucleic acid replication and mapping of the D1 chrorosore. Amer. J. Dis. Child. 111:83-89, 1966. Zabel, B. and Baurann, W. T‘risomie partielle pour la partie distale du bras long du chrorosone 15 par translocation X/ 15 maternelle . Ann. Genet. 20:285-289, 1977.