Male pseudohermaphroditism caused by steroid 5alpha-reductase deficiency is an 
autosomal recessive disorder. The enzyme steroid 5alpha-reductase 2 (encoded by 
the SRD5A2 gene) catalyses the conversion of testosterone to 
dihydrotestosterone, which is required for normal differentiation of the 
external male genitalia. This report describes the molecular analysis of the 
5alpha-reductase type 2 gene in a Brazilian patient who was raised as a female, 
underwent a reversal of gender role behavior, and is now a married man. This 
patient is a compound heterozygote bearing an A-->G mutation within exon 2, 
changing codon 126 from Glu to Arg on one allele and a novel single base 
deletion (418delT) causing a frameshift mutation at codon 140 in the same exon, 
on the other allele. This last mutation probably leads to the synthesis of a 
truncated protein, because a premature termination signal is created at codon 
159.