Glucocorticoid and mineralocorticoid replacement therapy, when required, needs to be maintained throughout life and is designed to prevent adrenal crisis and suppress excess androgen production in patients with congenital adrenal hyperplasia (CAH) attributed to 21-hydroxylase enzyme (21OHase) deficiency ( 2 ). The gene discussed is CYP21A2; the disease is hyperinsulinemic hypoglycemia, familial, 4.