A case of 16-ene-synthetase deficiency in male pseudohermaphroditism due to combined 17 alpha-hydroxylase/17,20-lyase deficiency.

A 17-year-old phenotypic female with primary hypergonadotropic amenorrhea, absence of secondary sexual development, hypertension and 46 XY karyotype is presented. Hormonal analysis revealed very low levels of testosterone, dehydroepiandrosterone, androstenedione, estrogens, cortisol and high levels of ACTH, progesterone, deoxycorticosterone and corticosterone. Enzyme studies of the testicular tissue after bilateral gonadectomy showed absence of 17 alpha-hydroxylase and 17,20-lyase activity as well as 16-ene-synthetase activity. This enzyme catalyzes the reaction from pregnenolone to 5,16-androstadien-3 beta-ol, a sex pheromone precursor. The other enzyme systems leading from pregnenolone to testosterone were intact. This is the first report of male pseudohermaphroiditism in which the combination of 17 alpha-hydroxylase, 17,20-lyase and 16-ene-synthetase deficiency is described, indicating that all these activities might be associated with the same protein.