Reciprocal translocation between Y chromosome long arm euchromatin and the short arm of chromosome 1

A case with an apparently balanced reciprocal translocation between the long arm of the Y chromosome and the short arm of chromosome 1 t(Y;1)(q11.2;p34.3) is described. The translocation was found in a phenotypically normal male ascertained by infertility and presenting for intra-cytoplasmatic sperm injection treatment. Histological examination of testicular biopsies revealed spermatogenic failure. Chromosome painting with probes for chromosome 1 and for the euchromatic part of the Y chromsome confirmed the translocation of euchromatic Y chromosomal material onto the short arm of chromosome 1 and of a substantial part of the short arm of chromosome 1 onto the Y chromosome. Among the Y/autosome translocations, the rearrangements involving long arm euchromatin of the Y chromosome are relatively rare and mostly associated with infertility. Microdeletion screening at the azoospermia locus revealed no deletions, suggesting another mechanism causing infertility in this translocation carrier.     

Mapping the short arm of human chromosome 16

Physical mapping of 13 different breakpoints on the short arm of chromosome 16 using previously mapped probes and the subsequent mapping of additional probes enabled the division of this portion of the chromosome into six different intervals. D16S94 was mapped between HBA and D16S80 and is closer to PKD1 than either HBA or D16S80. A tight linkage group which includes FRA16A, D16S8, and D16S79 was identified. Seven breakpoints, including FRA16A, could not be separated by probe localizations. This study provides the basis for the development of detailed maps of the short arm of chromosome 16.     

Short arm deletion of chromosome 14

Summary 3 cases with a Do-chromosome, designated by autoradiography as a No. 14, are presented by the authors. The first case was a mentally retarded boy with minor malformations. Cases 2 and 3 had normal phenotypes and were detected by cytogenetic investigation of family members of a mentally retarded boy with a ring G chromosome. The 14 p-was the only caryotype abnormality in the father (case 2). It was associated with other abnormalities in the daughter (case 3) who had a D/G translocation of the centric fusion type (46, XX, 15-,21-, t(15p21p)+, t(15q21q)+).

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Zusammenfassung 3 Fälle mit einem Dp-Chromosom, das durch Autoradiographie als ein Nr. 14 identifiziert werden konnte, werden dargestellt. In dem ersten Fall bestanden Debilität und unbedeutende morphologische Anomalien. Fall 2 und 3 hatten einen normalen Phänotyp und wurden im Verlaufe von cytogenetischen Untersuchungen von Familienangehörigen eines debilen Jungen mit einem Ring 22 entdeckt. Das 14p-Chromosomwar die einzige Anomalie im Karyoy[ des Vaters (Fall 2). Bei der Tochter (Fall 3) bestand außerdem eine D/G-Translokation (46,XX,15-,21-,t(15p21p)+,t(15q21q)+).

     

Interstitial deletion of the long arm of chromosome 3

A patient with multiple congenital malformations and developmental delay is reported. Her karyotype is 46,XX,del(3)(q23q25).     

Partial monosomy of the short arm of chromosome 9

Summary A 10-year-old girl with partial deletion of the short arm of chromosome 9 is reported; karyotype: 46,XX,del(9)(p22). This syndrome results in a distinctive craniofacial dysmorphism with trigonocephaly and contrasting midfacial hypoplasia. Partial monosomy 9p was the result of a paternal de novo germinal deletion in this case.     

Fragile site long arm chromosome 16

Summary A fragile site at the long arms (q21) of chromosome 16 was found in two persons, each of whom became the parent of a child with a de novo structural chromosome abnormality—a balanced autosomal translocation and an autosomal deletion. The question of an increased risk of structural chromosome abnormalities in the offspring of persons with fragile site long arm 16 is discussed.     

Detection of microdeletions in the short arm of the X chromosome by chromosome stretching

The present study was focused on the resolution of "chromosome stretching". In order to determine if this method can be used for the detection of microdeletions, the p-arms of 13 normal X chromosomes were stretched as well as of those with three different deletions of known size within the DMD/BMD region in Xp21 (case A: 0.42-0.45 Mb, case B: 2.3-2.9 Mb and case C: 3.0-3.5 Mb). The process of band splitting was recorded on a video-tape and the resulting banding pattern analyzed. Stretching of the normal Xp-arms led to a splitting on a maximum band level of 1400 and showed in all cases an identical banding pattern with 13 Giemsa-dark subbands. All new Giemsa-dark and -light subbands were derived from the three initial Giemsa-dark bands at the 400 band level according to ISCN (1995): five subbands from Xp21, four subbands from Xp11.3 and Xp22.2, respectively. The origin of these subbands is partly in contrast to the high resolution ISCN (1995) ideograms: subband Xp11.22 does not originate from the Giemsa-light band Xp11.2, but from the Giemsa-dark band Xp11.3; Xp22.12 originates from Xp21; Xp22.32 from Xp22.2. Stretching of the chromosomes containing deletions showed in cases A and B no differences in banding patterns and splitting order compared to normal X chromosomes. Only in patient C was a significant difference with the normal pattern visible due to the absence of one dark subband. In this case only four Giemsa-dark subbands derived from band Xp21. Thus, at least in the DMD/BMD region, the minimal size of a deletion detected by chromosome-stretching-generated high-resolution ideograms is about 3.0-3.5 Mb.     

Interstitial deletion of the long arm of chromosome 7

Summary Chromosome studies were carried out in a girl because of psychomotor retardation and difficulty in swallowing. The girl was admitted to hospital for the first time when 25 months old. The most characteristic signs revealed by the physical examination were short distal ulnar phalanges, clitoral hypertrophy, and very thin outer ear cartilages.An interstitial deletion of the long arm of chromosome 7 was observed: 7q22::7q31.Laboratory investigations revealed a remarkably high level of IgG, immunoglobulin, and an elevated value of serum FSH. No evidence of gene loci located at the deleted part of chromosome 7 were found.     

Interstitial delection of the long arm of chromosome 8

Summary This report describes a polymalformed 18-month-old male with an interstitial deletion of the long arm of chromosome 8. His karyotype is: 46,XY,del(8)(q21).     

Partial deletion of the long arm of chromosome 18

Summary A female infant with mental retardation and multiple somatic anomalies is described. The karyological analysis disclosed the partial deletion of the long arm of chromosome 18 in cells of probands peripheral blood culture. Repeated investigations of probands mothers peripheral blood cultures disclosed the presence of various chromosomal aberrations in 25–70% of cells.     

Interstitial deletion of the short arm of chromosome 3

Summary A de novo interstitial deletion of the short arm of chromosome 3 was prenatally diagnosed in a male fetus, karyotype 46,XY,del(3)(pterp14.2::p11qter). The fetus had craniofacial dysmorphisms, a single transverse palmar crease, ulnar deviation in the wrists, cardiovascular anomalies, a slight ureteric dilatation and a mobile caecum. Our observations are compared with five other cases with interstitial deletion of the short arm of chromosome 3 to delineate further the proximal 3p deletion syndrome. The gene for beta-galactosidase-1 (GLB-1) has previously been assigned to chromosome 3(p21q21). The absence of a gene dosis effect for GLB-1 in this study indicates exclusion of GLB-1 from 3(p11p14.2).     

Interstitial deletion of the long arm of chromosome 11

A female patient with an interstitial deletion of the long arm of chromosome 11 is described. Her growth and psychomotor development were normal. She showed some facial dysmorphic features including cleft lip/palate, a probable cardiac defect and a triphalangeal thumb. A clinical correlation with similar cases is presented.     

Extreme variant of the short arm of chromosome 15

Using fluorescence in situ hybridization, primed in situ labelling, and conventional cytogenetic staining we have characterized an excessively enlarged short arm of chromosome 15. The likely mechanism explaining this variant chromosome involves amplification of rDNA sequences followed by inverted insertional translocation between the enlarged sister chromatids of the short arm of chromosome 15. Received: 9 March 1995 / Revised: 16 October 1995