Hypergonadotropic hypogonadism in a patient with inv ins (2;4)

We report on a 30-year-old man with azoospermia, primary hypogonadism and minor dysmorphic features who carried a balanced insertional chromosome translocation inv ins (2p24;4q28.3q31.22)de novo. Molecular cytogenetic analyses of the chromosome breakpoints revealed the localization of the breakpoint in 4q28.3 between BACs RP11-143E9 and RP11-285A15, an interval that harbours the PCDH10 gene. In 4q31.22, a breakpoint-spanning clone (RP11-6L6) was identified which contains the genes LSM6 and SLC10A7. On chromosome 2, BACs RP11-531P14 and RP11-360O18 flank the breakpoint in 2p24, a region void of known genes. In conclusion, the chromosome aberration of this patient suggests a gene locus for primary hypogonadism in 2p24, 4q28.3 or 4q31.2, and three possible candidate genes (LSM6, SLC10A7 and PCDH10) were identified by breakpoint analyses.

Comparative architectural aspects of regions of conserved synteny on human chromosome 11p15.3 and mouse chromosome 7 (including genes WEE1 and LMO1)

Human chromosome 11p15.3 is associated with chromosome aberrations in the Beckwith Wiedemann Syndrome and implicated in the pathogenesis of different tumor types including lung cancer and leukemias. To date, only single tumor-relevant genes with linkage to this region (e.g. LMO1) have been found suggesting that this region may harbor additional potential disease associated genes. Although this genomic area has been studied for years, the exact order of genes/chromosome markers between D11S572 and the WEE1 gene locus remained unclear. Using the FISH technique and PAC clones of the flanking markers we determined the order of the genomic markers. Based on these clones we established a PAC contig of the respective region. To analyse the chromosome area in detail the synteny of the orthologous region on distal mouse chromosome 7 was determined and a corresponding mouse clone contig established, proving the conserved order of the genes and markers in both species: "cen-WEE1-D11S2043-ZNF143-RANBP7-CEGF1- ST5-D11S932-LMO1-D11S572-TUB-tel", with inverted order of the murine genes with respect to the telomere/centromere orientation. The region covered by these contigs comprises roughly 1.6 MB in human as well as in mouse. The genomic sequence of the two subregions (around WEE1 and LMO1) in both species was determined using a shotgun sequencing strategy. Comparative sequence analysis techniques demonstrate that the content of repetitive elements seems to decline from centromere to telomere (52.6% to 34.5%) in human and in the corresponding murine region from telomere to centromere (41.87% to 27.82%). Genomic organisation of the regions around WEE1 and LMO1 was conserved, although the length of gene regions varied between the species in an unpredictable ratio. CpG islands were found conserved in putative promoter regions of the known genes but also in regions which so far have not been described as harboring expressed sequences.

Molecular cloning and chromosomal assignment of the human homologue of the rat cGMP-inhibited phosphodiesterase 1 (PDE3A)--a gene involved in fat metabolism located at 11p 15.1

We have cloned the coding region of a human gene, whose predicted amino acid sequence shows 88% homology and higher correspondence in functional domains to the rat cGMP inhibited phosphodiesterase gene (PDE3A). In concordance with the expression data of the rat PDE3A gene, a 5.3-kb transcript of the human cGMP-inhibited phosphodiesterase gene is shown in Northern blot analysis to be highly expressed in adipose tissue. In addition, weaker expression is seen in pancreas, skeletal muscle, liver, placenta, and heart. cDNA clones from the homologue mouse gene were isolated and sequenced spanning a highly conserved region coding for a C-terminal located catalytic core region of this enzyme family. Using a genomic cosmid clone of human PDE3A for fluorescence in situ hybridization, the gene was mapped to chromosomal region 11p15 and regionally sublocalized by PCR on a human-hamster somatic hybrid-cell mapping panel to 11p15.1-p2. Based on comparative linkage data in mouse and rat this chromosomal location is suggested to contain genes involved in complex diseases like obesity and diabetes mellitus type II. Therefore, a possible involvement of the human PDE3A gene in these polygenic traits is discussed, taking into account the prominent role of the rat PDE3A gene product in the antilipolytic action of insulin in adipocytes.