CYP17A1 and congenital adrenal hyperplasia: 46,XY DSD with low testosterone and increased precursors can be caused by several variants of CAH, namely by 17α-hydroxylase (CYP17A1) deficiency, ORD and 3βHSD2 deficiency, caused by inactivating mutations in the corresponding genes CYP17A1, POR and HSD3B2, respectively.