XY GONADAL-DYSGENESIS AND SRY

During mammalian embryogenesis, the presence of the SRY gene determine s the bipotential gonad to develop as a testis. 46, XY sex reversal ha s been described in man. It is associated with an essentially female p henotype 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 analysi s 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 reversa l. No relationship was found between the SRY status and the presence o r absence of gonadoblastoma. However, a correlation was observed betwe en the SRY genotype and the histology of the gonad. A mutant in SRY is associated with a completely dysgenetic gonad. The presence of immatu re testicular tubules is usually observed when SRY is normal. These la tter results suggest the existence of as yet unidentified testis deter mining genes.