3β-hydroxysteroid dehydrogenase deficiency

3β-hy·droxy·ste·roid de·hy·dro·gen·ase de·fi·cien·cy (hi-drok″se-sterґoid de-hiґdro-jən-ās) an autosomal recessive disorder of steroidogenesis caused by mutation in the HSD3B2 gene (locus: 1p13.1), which encodes 3β-hydroxysteroid dehydrogenase, resulting in several forms of one type of congenital adrenal hyperplasia (type II): the classic forms are salt-wasting and the milder non–salt-wasting, and the nonclassic form is late onset. The enzyme deficiency is present in adrenals and gonads; pathways to cortisol, sex steroids, and aldosterone are blocked; and pregnenolone, 17α-hydroxypregnenolone, and dehydroepiandrosterone are elevated in plasma. Males affected during fetal life are pseudohermaphroditic; both sexes have slight postnatal virilization. Most common is the mildest form (late onset) but of the classic forms, salt-wasting is predominant. See also table at hyperplasia.