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).[1][2] As a result, higher levels of 17OH-pregnenolone appear in the blood with adrenocorticotropic hormone (ACTH) challenge, which stimulates adrenal corticosteroid synthesis.