CYP21A2 and congenital adrenal hyperplasia due to cytochrome P450 oxidoreductase deficiency: The discovery of the molecular basis of POR deficiency (PORD) in 2004 (40, 41) solved the puzzle previously posed by patients with a unique urine steroid profile published 20 years earlier, indicating the concurrent presence of CYP21A2 and CYP17A1 deficiencies (42).