CYP21A2 and hyperinsulinemic hypoglycemia, familial, 4: Most of the patients (96 of 104, 92%) had a genetically confirmed diagnosis of CAH due to 21-hydroxylase (CYP21A2) deficiency in 94 patients (90%), 11-β-hydroxylase (CYP11B1) deficiency in 1 patient (1%), and P450 oxidoreductase (POR) deficiency in 1 patient (1%).