MALE PSEUDOHERMAPHRODITISM RESULTING FROM A NOVEL MUTATION IN THE HUMAN STEROID 5-ALPHA-REDUCTASE TYPE-2 GENE (SRD5A2)

The enzyme steroid 5 alpha-reductase, via NADPH, catalyses the convers ion of testosterone to dihydrotestosterone, which is required for the embryonic differentiation of the external male genitalia and the prost ate. An impairment of this reaction causes a form of male pseudohermap hroditism in which genetic males differentiate predominantly as phenot ypic females. Molecular analysis of the 5 alpha-reductase type 2 gene in a patient with confirmed biochemical 5 alpha-reductase deficiency h as resulted in the identification of a novel mutation, GAA to AAA, at codon 200. This mutation produces an amino acid change from glutamic a cid to lysine, and may affect the ability of the enzyme to bind its co -factor.