HSD3B2 is a human gene that encodes for 3beta-hydroxysteroid dehydrogenase/delta(5)-delta(4)isomerase type II or hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 2. It is principally expressed in steroidogenic tissues and is essential for steroid hormone production. A notable exception is the placenta where HSD3B1 is critical for progesterone production by this tissue.
Mutations in the HSD3B2 gene result in the condition congenital adrenal hyperplasia due to 3 beta-hydroxysteroid dehydrogenase deficiency.