CYP21A2 and congenital adrenal hyperplasia: Several neonatal screening programmes conducted worldwide report the incidence of CAH to be approximately 1 in 10,000 to 1 in 20,000 live births.3 The most common cause of congenital adrenal hyperplasia, accounting for more than 95% of all cases, is due to a deficiency of 21-hydroxylase, an enzyme encoded by the CYP21A2 gene located on the short arm of chromosome 6.1 In CAH enzymatic defect in the corticosteroid and mineralocorticoid pathway shunts the steroid precursor to alternative derivatives like androgen and sex steroid.