17 alpha-hydroxylase deficiency in a genetic male and female sibling pair.

The diagnosis of congenital adrenal hyperplasia due to a deficiency of the enzyme 17 alpha-hydroxylase was made in a genetic male and female sibling pair born of parents who were first cousins. The genetic male was a phenotypic female who presented with primary amenorrhea and mild hypertension. The genetic female exhibited absence of secondary sexual characteristics and severe hypertension. The plasma steroid data confirmed the diagnosis of 17 alpha-hydroxylase deficiency in both subjects: low 17 alpha-hydroxyprogesterone, elevated desoxycorticosterone, elevated corticosterone and elevated progesterone. These are the first case reports of 17 alpha-hydroxylase deficiency in a male-female sibling pair, and they add support to the hypothesis that this is an autosomal recessive disorder.