Yasuo Nakagome

Chondrodysplasia punctata with X;Y translocation.

SummaryWe have studied a family in which the mother and her son were carriers of an X;Y translocation, der(X)t(X;Y) (p22.3;q11). The mother was of slightly short stature and had mildly short upper extremities. The son had epiphyseal punctate calcifications, mildly short extremities, a flattened nasal bridge, and mental retardation (chondrodysplasia punctata). The extra bands on the short arm of the X chromosome were identified as deriving from the long arm of the Y chromosome, using in situ hybridization with a Y-chromosome-specific DNA probe (pHY10). The chondrodysplasia punctata seen in our case may be associated with the abnormality of the distal short arm of the X chromosome caused by X;Y translocation.

A 6p trisomy detected in a family with a “giant satellite”

SummaryA very large (giant) satellite was observed on one of the D-group chromosomes of a malformed and mentally retarded infant and her father. Detailed cytogenetic studies revealed that the giant satellite represented, in fact, a der(15) chromosome of translocation t(6;15)(p21;p12 or 13). The proposita was trisomic for a part of 6p(6pter → 6p21). The father was a balanced carrier, however, the deletion of the short arm of a No. 6 was hard to detect in routine karyotype analysis.

Mental retardation, malformation syndrome and partial 7p monosomy [45, XX, tdic (7;15) (p21;pll)]

A mentally retarded and malformed girl is described. Her karyotype was 45, XX, tdic(7;15) (p21;p11), i.e. she was monosomic for bands 7p22 and a part of 7p21. Only one of the two centromeres of the dicentric chromosome appeared to be functioning. The C‐band positive material was retained by both centromeres (or adjacent to them). However, the Cd‐band positive structure was absent in the presumably nonfunctioning centromere region.

High-resolution banding by treating cells with acridine orange before fixation

Treatment of standard blood cultures with acridine orange (20–25 ug/ml) during the final 30 min of culture, 30–90 min after the addition of Colcemid, provides a simple method for obtaining elongated h

High-resolution studies in patients with aniridia-Wilms tumor association, Wilms tumor or related congenital abnormalities

SummaryWe attempted to determine wheter all cases of AWTA (anirida-Wilms tumor association) or any of the following groups of patients show 11p deletion: cases of Wilms tumor with congenital abnormalities other than aniridia, those without any congenital abnormalities, tumor itself in cases of Wilsm tumor without constitutional 11p deletion and cases of aniridia or hemihypertrophy without Wilms tumor. We studied a total of 29 index patients including five cases of AWTA, four cases of Wilms tumor with various congenital abnormalities, 16 cases of Wilms tumor without other abnormalities, three cases of aniridia in one of which Wilms tumor developed later and a case of hemihypertrophy.In all five cases of AWTA and in a case of aniridia who later developed Wilms tumor, 11p deletion involving the p13 band was detected. The mother of the latter also showed an identical 11p deletion. The common segment of deletion was the middle part of the p13. Two possible hypotheses on the mechanism through which Wilms tumor might develop were evaluated, based on the distribution of break points. All other cases, including five with tumor culture, showed a normal karyotype.

Two cases of 8p trisomy in one sibship

Two cases of 8p trisomy in one sibship are presented. The father was a balanced carrier of a translocation rep (8;13) (p11; q34). Case 1 was a 2‐year‐old boy with multiple minor anomalies and severe mental retardation. Giemsa banding studies revealed that he was trisomic for the greater part of 8p (8p11 → pter). When his mother became pregnant again, amniocentesis was carried out in the 17th week of gestation. The fetus (Case 2) was shown to have the same 8p trisomy as Case 1. The pregnancy was terminated in the 22nd week. An autopsy revealed no major anomalies. Clinical features of cases with 8 and 8p trisomy are reviewed briefly.

Mental Retardation and Congenital Malformations Associated with a Ring Chromosome 9

SummaryA 46,XY,r(9)(p24q34) complement was observed in a 35-month-old boy with multiple congenital anomalies. The main clinical features included intrauterine growth retardation, dwarfism, microcephaly, peculiar face, undescended testes, seizures and severe psychomotor retadation.It appears that 4 reported cases of r(9) can be devided into two groups. Three of them, including the present case, share clinical features with those of cases with 9p-. On the other hand, one case showed a different combination of malformations.

Maternally transmitted extra ring (21) chromosome in a boy with Down's syndrome.

SummaryAn 11-month-old boy with typical Downs syndrome is presented. His karyotype was 47,XY,+r(21); the erythrocyte superoxide dismutase-1 (SOD-1) activity was elevated. His phenotypically normal mother showed 46,XX,r(21) karyotype and normal SOD-1 activity. Analysis of chromosomal heteromorphism revealed that in addition to the ring, a normal chromosome 21 was transmitted from the mother.

Pitfalls in the use of chromosome variants for paternity dispute cases.

SummaryA huge ‘satellite’ (22s+) was observed in a mentally retarded and malformed girl. It consisted of constitutive heterochromatin based on the C-band technique (CBG). In neither of the parents was the variant observed. Genetic marker studies revealed that the father was, indeed, the father of the proposita (probability, 99.8%).It is emphasized that caution must be taken in the use of chromosome variants for paternity dispute cases.

Y-chromatin positive cells in the smear preparations of the gonad from an XX male

SummaryAn ambisexual male infant showed a normal female karyotype by the leukocyteculture technique in two different occasions. Cultured fibroblasts from the right gonad had also a 46,XX complement. They were Y-chromatin negative. To our surprise, Y-chromatin was observed in 96% of the nuclei in smears from the uncultured gonad. It is emphasized that the examination of the uncultured gonad by the quinacrine technique is mandatory in the study of “XX males”.