Male pseudohermaphroditism caused by nonsalt-losing congenital adrenal hyperplasia due to 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) deficiency.

We observed a boy with ambiguous genitalia and normal testes. Steroid analyses performed during newborn age surprisingly were inconclusive basally and after hCG stimulation, but showed an insufficient testosterone response. Possibly during the early postnatal period the 3 beta-HSD activity in peripheral tissues may have been sufficient to substitute for the deficient 3 beta-HSD activity in the adrenal and gonads. In contrast at 11 and 22 months basal as well as ACTH stimulated levels of 17OHPreg, DHEA and testosterone were typical for a 3 beta-HSD defect.