Most common enzyme deficiency in congenital adrenal hyperplasia is

congenital adrenal hyperplasia is a group of autosomal recessive defects in steroid synthesis characterised by deficiency of adrenocoical hormones The commonest form of congenital adrenal hyperplasia accounting for about 90% of cases is due to deficiency of 21-alpha hydroxylase It is associated with diminished synthesis of coisol and aldosterone Reference: Ghai TB of pediatrics 8th edition pg 526