CYP17A1 and congenital adrenal hyperplasia: For example, in humans, CPR is involved in steroidogenesis, bone formation, and drug metabolism [48], and mutations in the human CPR result in reduced activities of steroid metabolising enzymes, CYP17A1 (17, α-hydroxylase)/17,20 lyase), and CYP19A1 (aromatase), causing a rare form of congenital adrenal hyperplasia characterised by adrenal insufficiency, genital anomalies, and bony malformations resembling Antley–Bixler syndrome [49,50].