Trisomy for the short arm of chromosome No. 10

To the authors knowledge there is a single previous report of confirmed trisomy for the short arm of chromosome No 10 (Hustinx et al., 1974). In this paper we present a further case of trisomy 10p, resulting from 3 : 1 segregation of maternal balanced translocation, t(3;10)(q;11), in a female infant aged 7 months and showing numerous somatic anomalies.     

Genetic counselling in carriers of reciprocal chromosomal translocations involving short arm of chromosome X

A central concept in genetic counselling is the estimation of the probability of occurrence of unbalanced progeny at birth and other unfavourable outcomes of pregnancy (miscarriages, stillbirths and early death). The estimation of the occurrence probability for individual carriers of four different X-autosome translocations with breakpoints at Xp, namely t(X;5)(p22.2;q32), t(X;6)(p11.2;q21), t(X;7)(p22.2;p11.1), and t(X;22)(p22.1;p11.1), is presented. The breakpoint positions of chromosomal translocations were interpreted using GTG, RBG and FISH-wcp. Most of these translocations were detected in women with normal phenotype, karyotyped because of repeated miscarriages and/or malformed progeny. A girl with very rare pure trisomy Xp22.1-->pter and a functional Xp disomy was ascertained in one family and her clinical picture has been described in details. It has been suggested that not fully skewed X chromosome inactivation of X-autosome translocation with breakpoint positions at Xp22 (critical segment) could influence the phenotype and risk value. Therefore, the X inactivation status was additionally evaluated by analysis of replication banding patterns using RBG technique after incorporation of BrdU. In two carriers of translocations: t(X;5)(p22.2;q32) and t(X;7)(p22.2;p11.1), late replication state of der(X) was observed in 5/100 and 10/180 analysed cells, respectively. In these both cases the breakpoint positions were clustered at the critical segment Xp22.2. In two other cases, one with the breakpoint position within [t(X;22)(p22.1;p11.1)] and one outside the critical region [t(X;6)(p11.2;q21)], fully skewed inactivation was seen. Therefore, we suggest that neither the distribution of the breakpoint positions nor fully skewed inactivation influenced the phenotype of observed t(X;A) carriers. The occurrence probabilities of the unbalanced progeny were calculated according to Stene and Stengel-Rutkowski along with application of updated available empirical data. In the studied group the values of occurrence probability for unbalanced offspring at birth ranged from 2.1% to 17%. Information on the magnitude of the individual figures may be important for women carrying a reciprocal X;A translocation when deciding upon further family planning.     

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.     

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.     

The gene encoding human vimentin is located on the short arm of chromosome 10.

The gene for vimentin, an intermediate-filament protein, is growth regulated. We used Southern blot analysis and in situ chromosome hybridization to determine the location of the human vimentin gene. Our results show that there is only one copy of the vimentin gene and that it is located on the short arm of chromosome 10 (10pter-10q23) close to the interleukin-2 receptor gene, which is also growth regulated. In situ hybridization studies suggest that the most likely location of the vimentin gene is 10p13. Sequence similarities and homologies of human vimentin to other genes are 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     

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).     

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.     

Regional localisation of X chromosome short arm probes

Summary Nine human X chromosome-specific clones have been isolated by screening an X-chromosomal genomic library with fetal muscle cDNA. Five of the clones have been localised to the short arm and four to the long arm. The short arm probes have been regionally assigned using a panel of somatic cell hybrids. They have been mapped further using a series of DNA samples from male patients with different deletions of the region Xp21, and having complex phenotypes including Duchenne muscular dystrophy. The use of these probes in the mapping of the short arm of the X chromosome is discussed.     

Partial deletion of the short arm of chromosome 8]

Partial monosomy 8p is reported in a patient with mild mental deficiency and a facial dysmorphia (a triangular mandible and a peculiarly shaped nose with straight parallel margins).     

Radiation mapping of the short arm of swine chromosome 2

In recent years, maps of mammalian genomes have been acquiring increasingly higher resolution. Integration of maps of different types has become possible. As a tool in integrating maps of mammalian genomes of different types, high-resolution mapping with radiation-induced hybrids (RH) is used. Here, we present an RH6000 map of the short arm of porcine chromosome 2. The map contains 15 microsatellites and five genes (for parathyroid hormone, lactate dehydrogenase A, myogenic factor, follicle-stimulating hormone beta, and calpain I). The RH panel was obtained on the basis of a hybrid cell line bearing the single porcine chromosome 2 against the background of mink chromosomes. The mean frequency of preserving markers examined in the panel was 18.3%. Integration of four genes in the panel and a comparison of gene order in homologous regions of human and porcine chromosomes are presented.     

Localization of HLA on the short arm of chromosome 6

Summary A detailed marker gene study in a large Dutch kindred segregating for a reciprocal translocation between the chromosomes 6 and 20, t(6;20) (p21;p13), revealed a close linkage between the HLA genes and the breakpoint on the short arm of 6. During this study an apparent peak lod score of 2.9 was obtained at a recombination value of 0.05 for a linkage between HLA and the breakpoint, indicating that the chromosomal region, carrying the HLA genes, is situated near the breakpoint in band 6p21 close to the transition to 6p22.     

Pure partial trisomy of the short arm of chromosome 5

Summary We describe a male infant with multiple dysmorphic features who is trisomic for chromosome segment 5p13.325p14.2 as a result of recombination aneusomy. His father is a balanced carrier of an inverted insertion of this chromosome segment. The clinical features of this patient are compared with those of other patients with isolated partial 5p trisomy reported in the literature.