3β-Hydroxysteroid dehydrogenase II deficient congenital adrenal hyperplasia (3β-HSD CAH) is an uncommon form of congenital adrenal hyperplasia (CAH) resulting from a mutation in the gene for one of the key enzymes in cortisol synthesis by the adrenal gland 3β-hydroxysteroid dehydrogenase (3β-HSD) type II (HSD3B2).