CYP11B1 and congenital adrenal hyperplasia: CYP11B1 (11β-hydroxylase) deficiency, caused by a mutation in the CYP11B1 gene, is a rare form of CAH, accounting for 5-8% of CAH cases with a global estimated prevalence of 1: 100.000 in live births (1), but in Indonesia, the prevalence has not yet been reported.