CAH is an autosomal recessive disease caused by mutations or deletions in CYP21A2, the gene encoding steroid 21-hydroxylase.6 Based on the data from neonatal screening, the prevalence of congenital adrenal hyperplasia (CAH) is 1 in 15,000 live births.3,7. The gene discussed is CYP21A2; the disease is congenital adrenal hyperplasia.