Which is the most common variant of congenital adrenal hyperplasia?: (A) 11b hydroxylase deficiency, (B) 17a hydroxylase deficiency, (C) 3b hydroxyl-steroid dehydrogenase, (D) 21 hydroxylase deficiency
Answer is D. Mutations in CYP21A2 which leaads to 21 hydroxylase deficiency is the most prevalent cause of CAH responsible for 90-95% of cases.