Neutral 17beta-hydroxysteroid oxidoreductase deficiency in testes causing male pseudohermaphroditism in an infant.

A deficiency of neutral 17beta-hydroxysteroid oxidoreductase activity in testes has been diagnosed in a n infant with male pseudohermaphroditism. In vivo stimulation tests of testicular endocrine function with human chorionic gonadotrophin provided an accurate diagnosis in contrast to estimates of enzymic activity in vitro in testes and other tissues. The discrepancy in testes may be due to the absence of gonadotrophin stimulation in the latter studies. The in vitro studies show that there are at least two forms of 17beta-hydroxysteroid oxidoreductase under independent genetic control and that only one form is localized to the testes. The diagnosis before puberty has allowed early treatment by removal of the abnormal testes which should prevent the usual presenting clinical signs of marked masculinizatin and hirsutism at puberty.