[A case of pseudo-vaginal, perineoscrotal hypospadia with 5-alpha reductase deficiency].

A case of pseudovaginal perineoscrotal hypospadia (PPSH) is presented. This autosomal recessive disorder, also termed incomplete male pseudohermaphroditism type 2, is mostly caused by a deficiency of 5 alpha-reductase, which controls the conversion of testosterone to 5 alpha-dihydrotestosterone. In genital skin fibroblasts, the activity of the 5 alpha-reductase was strongly reduced, compared with a normal male. The 5 alpha-reductase activity in nongenital skin fibroblasts, however, was in the range of the normal male control. For complete diagnostic evaluation of PPSH 5 alpha-reductase activity it should be determined simultaneously in genital and non genital skin fibroblasts. The conversion of T to DHT in genital skin fibroblasts of a patient with testicular feminisation (Tfm) was found to be of the same order of magnitude as in PPSH. This suggests, that the expression of 5 alpha-reductase is androgen-dependent.