[Study of sex determination gene (SRY) in 46,XY gonadal dysgenesis]

During mammalian embryogenesis, the presence of the SRY gene determines the bipotential gonad to develop as a testis. 46,XY sex reversal has been described in man. It is associated with an essentially female phenotype and a streak gonad. In a collaborative study, we analysed 36 patients with a 46,XY sex reversal. The testis determining region of the Y chromosome was analysed by Southern blotting and by DGGE analysis of the SRY open reading frame (orf). We found a total of 7 mutations in the testis determining region including the SRY gene. This brings to 19 the total number of mutations in SRY associated with sex reversal. No relationship was found between the SRY status and the presence or absence of gonadoblastoma. However, a correlation was observed between the SRY genotype and the histology of the gonad. A mutant in SRY is associated with a completely dysgenetic gonad. The presence of immature testicular tubules is usually observed when SRY is normal. These latter results suggest the existence of as yet unidentified testis determining genes.