Among the various causes of 46,XY DSD, 5α-reductase type 2 (encoded by SRD5A2) (4, 5, 6, 7, 8) or 17β-hydroxysteroid dehydrogenase type III (encoded by HSD17B3) deficiency (9, 10, 11) and alteration of steroidogenic factor 1 (SF-1; encoded by NR5A1) function (12, 13, 14, 15, 16, 17, 18, 19, 20) have been associated with virilization at puberty. This evidence concerns the gene SRD5A2 and disorder of sexual differentiation.