The gene coding for human anti-Müllerian hormone (AMH) was localized to subbands p13.2→p13.3 on chromosome 19, using in situ hybridization and Southern blot analysis of a panel of man-mouse and man-hamster somatic cell hybrids.

Alport syndrome (AS) is an hereditary glomerulonephritis that is mainly inherited as a dominant X-linked trait. Structural abnormalities in the type IV collagen alpha 5 chain gene (COL4A5), which maps to Xq22, have recently been detected in several patients with AS. The association of AS with diffuse esophageal leiomyomatosis (DL) has been reported in 24 patients, most of them also suffering from congenital cataract. The mode of transmission and the location of the gene(s) involved in this association have not been elucidated. Southern blotting using cDNA probes spanning the whole COL4A5 and a 5' end COL4A5 genomic probe showed that three out of three patients with the DL-AS association had a deletion in the 5' part of the COL4A5 gene extending beyond its 5' end. This indicates that the same gene, COL4A5, is involved in classical AS and in DL-AS and that the transmission of DL-AS is X-linked dominant. These results also suggest that leiomyomatosis might be due to the alteration of a second gene involved in smooth muscle cell proliferation, which is located upstream of the COL4A5 gene, and that there might be a contiguous gene deletion syndrome, involving at least the genes coding for congenital cataract, DL and AS.

Bazex-Dupré-Christol syndrome is an inherited condition with skin cancer predisposition characterized by follicular atrophoderma, hypotrichosis, and early onset of multiple basal cell carcinomas. Previous reports suggested an X-linked mode of inheritance. We therefore performed linkage analysis with microsatellite markers of the X chromosome in three families. We obtained evidence for X-linkage and regional assignment to Xq24-q27 of this syndrome (maximal lod score = 5.26 with a recombination fraction of 0% at the DXS1192 locus). This represents a first step towards the identification of a gene involved in hair follicle development and skin tumor formation.

The type IV collagen a5 chain (

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