CYP21A2 and Adrenal insufficiency: Autoantibodies against steroid 21-hydroxylase (CYP21A2), steroid 17α-hydroxylase (CYP17A1), and cytochrome P450 family 11 subfamily A member 1 (CYP11A1) have been detected in many APS-1 patients with Addison’s disease years before adrenal insufficiency became clinically apparent (23).