<prompt> Most common enzyme deficiency in congenital adrenal hyperplasia is3 beta hydroxylase11 beta hydroxylase17 hydroxylase21 alfa hydroxylase  <response>: 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 