This reliance is reflected in the clinical observation that premature ovarian failure, oophoritis, primary testicular failures and autoantibodies against the steroidogenic enzymes, 21-hydroxylase (CYP21A1), steroid 17-alpha hydroxylase (CYP17A1) and P450scc (CYP11A1) constitute common autoimmune features of APS-1 (Betterle and Zanchetta 2003). Here, CYP17A1 is linked to primary ovarian failure.