Type C brachydactyly transmitted through four generations

We report a type C brachydactyly transmitted through four generations, with incomplete penetrance and feet abnormalities in the proposita.     

Molecular characterization of a Y;15 translocation segregating in a family

Summary We have used Y-specific and Y-derived DNA probes for in situ hybridization and Southern blotting analysis to characterize a Y;15 translocation showing normal Mendelian inheritance in a family. Cytogenetically there appeared to be an unbalanced translocation of Yqh to 15p; this translocation may be considered as a prototype of those translocations between Yq and the short arm of an acrocentric chromosome which have a population incidence of approximately 1 in 2,000. Our molecular studies showed that, in all probability, the breakpoints were near the border between Yq11.23 and Yq12, and in 15p11, respectively; the translocation is abbreviated t(Y;15)(q12;p11). Using the Y-specific probe pY431 in a quantitative Southern hybridization assay, normal females had no hybridization, female carriers and normal men had the same amount, and male carriers had twice that amount. Cytogenetic analysis and quantitative in situ hybridization using probes pY431 and pY3.4 were consistent with the hypothesis that the portion of Yq translocated to 15p comprised all of Yq12 and none of Yq11. The absence of Southern hybridization with probes specific for Yp and Yq11 confirmed this observation. Even though the family was ascertained through two brothers who both had schizophrenia and were carriers of the translocation, the clinical evaluation of a total of nine individuals with the translocation and five without it did not suggest its association with an abnormal phenotype.     

Familial Y/22 translocation in a woman

A phenotypically normal 35-year-old woman who had a malformed fetus was found to have a Y/22 translocation. One brother as well as a sister and her three children also have the Y/22 chromosome while another sister lacks it. The problem raised by the presence of this translocated chromosome for genetic counseling, especially for prenatal diagnosis, is emphasized.     

A sterile male with 45,X0 and a Y;22 translocation

Summary Cytogenetic analysis of a 20-year-old sterile male revealed a 45,X0 karyotype with no evidence for Y-chromosomal material on any of the chromosomes analysed by Q-, G- and C-banding. DNA analysis with 17 different Y chromosome-derived probes revealed the presence of Yp DNA sequences in the patient's genome. In situ hybridization with the Yp-derived probe pJA36B disclosed a translocation of Y-chromosomal material onto the short arm of a chromosome 22.     

X/Y translocation in a family with Leri-Weill dyschondrosteosis

An X/Y translocation associated with Leri-Weill dyschondrosteosis (LWD) was detected in a boy and in his mother. FISH analysis with specific probes for SHOX and SRY displayed no signal on the der(X), while one signal for SHOX was detected on the normal X chromosome in the mother, and one signal each for SHOX and SRY was detected on the normal Y chromosome in the proband.     

Familial translocation 22/Y and partial autosomal trisomy in a young girl

Report on a translocation t(22;Y)(q12;p 13) with conservation of the NOR in normal members from 2 generations of a family. The proposita has in addition a small autosomal duplication, probably (1)(q44-ter) which could explain her mental deficiency.     

Partial trisomy of 11 and 22 due to familial translocation t(11;22) (q23;q11), inherited in three generations

Summary A 1-year-old girl with partial trisomy of 11 (q23qter) and 22 (pterq11) is presented. She had severe mental retardation, cleft palate, congenital heart disease, congenital dislocation of the hip, and other anomalies.The extra acrocentric chromosome was identified as der(22),t(11;22) (q23;q11) from a familial translocation and by G-and R-banding methods. The mother and the maternal grandfather were carriers of balanced rcp(11;22) (q23;q11) translocations.The possible relations between phenotypic features and the karyotypes of partial trisomy 11 and 22 are discussed.     

A further case of a 22;22 Robertsonian translocation associated with recurrent abortions

Summary A case of 22;22 Robertsonian translocation, identified in the husband of a woman who had five early abortions, is reported.     

Recurrent abortion associated with a balanced 22;22 translocation,or isochromosome 22q in a monozygous twin

Summary A 45,XX,t(22;22)(p11;q11) or 45,XX,i(22q) chromosomal rearrangement was found in a woman with a history of recurrent abortion. A twin sister did not have the translocation even though marker studies indicate that the twins are probably monozygotic.     

Centromeric inactivation in a dicentric human Y;21 translocation chromosome

A de novo dicentric Y;21 (q11.23;p11) translocation chromosome with one of its two centromeres inactive has provided the opportunity to study the relationship between centromeric inactivation, the organization of alphoid satellite DNA and the distribution of CENP-C. The proband, a male with minor features of Down’s syndrome, had a major cell line with 45 chromosomes including a single copy of the translocation chromosome, and a minor one with 46 chromosomes including two copies of the translocation chromosome and hence effectively trisomic for the long arm of chromosome 21. Centromeric activity as defined by the primary constriction was variable: in most cells with a single copy of the Y;21 chromosome, the Y centromere was inactive. In the cells with two copies, one copy had an active Y centromere (chromosome 21 centromere inactive) and the other had an inactive Y centromere (chromosome 21 centromere active). Three different partial deletions of the Y alphoid array were found in skin fibroblasts and one of these was also present in blood. Clones of single cell origin from fibroblast cultures were analysed both for their primary constriction and to characterise their alphoid array. The results indicate that (1) each clone showed a fixed pattern of centromeric activity; (2) the alphoid array size was stable within a clone; and (3) inactivation of the Y centromere was associated with both full-sized and deleted alphoid arrays. Selected clones were analysed with antibodies to CENP-C, and staining was undetectable at both intact and deleted arrays of the inactive Y centromeres. Thus centromeric inactivation appears to be largely an epigenetic event. Received: 30 January 1997; in revised form: 3 April 1997 / Accepted: 8 May 1997     

Familial aniridia and translocation t(4;11)(q22;p13) without Wilms' tumor

A family with dominantly inherited aniridia in three generations is presented. All three patients had an apparently balanced chromosome translocation t(4;11)(q22;p13). The patients were otherwise clinically normal and without signs of Wilms' tumor; their erythrocyte catalase activities were within the normal range. We suggest that in this family aniridia is caused either by a submicroscopic deletion at the translocation breakpoint 11p13 or by a position effect on the same chromosome segment. Furthermore, the loci for aniridia and Wilms' tumor susceptibility are separate. It follows that the WAGR complex is caused by a mutation of more than one gene located at 11p13. The theoretical implications of a presumably defective allele causing a mendelian dominant phenotype are discussed.     

Characterization of a (Y;4) translocation by DNA hybridization

Summary A phenotypically normal male with azoospermia was found to have a translocation between the short arm of the Y chromosome and the distal long arm of a chromosome 4. By cytogenetic analysis it could not be determined whether the translocation was reciprocal, nor whether it was balanced. In situ DNA hybridization with two pseudoautosomal and one Y-specific probe demonstrated that the breakpoint was on distal Yp and that there was Y chromosome material on 4q. Thus the translocation was reciprocal and could be characterized as t(Y;4)(pll;q32). There was no evidence for loss of Y-DNA sequences as judged by Southern blotting with Y-DNA probes. Thus the translocation may be balanced. We conclude that DNA hybridization can be used to refine considerably the cytogenetic analysis of such translocations.     

Polydactyly in four generations of an Algerian family with variable metacarpo-phalangeal relationship in an individual

We report an Algerian family in which four generations show polydactyly with variable numbers of metacarpals and phalanges. The extraordinary rearrangements of the metacarpals and phalanges shown in the X-rays are most unusual. The family is highly consanguineous. The mode of inheritance appears to be dominant with reduced penetrance and variable expression.     

Report of large kinship with familial translocation between chromosomes 21 and 22.

This paper reports a large kinship with a familial (21;22) translocation occurring in both the balanced and the unbalanced states. Recurrence risks for the (21;22) translocation in the unbalanced state are high (14%) for the offspring of female carriers as compared with those for the offspring of male carriers (4%), but the offspring of male carriers appear to have a much higher risk (50%) of being balanced carriers than those of female carriers (30%).