These include three patients (i.e., P09, P22, P28) with 5-alpha-reductase deficiency due to biallelic mutations of the SRD5A2 gene, and four patients with idiopathic hypogonadotropic hypogonadism due to mutations of KAL1 (i.e., P27, P32), PROKR2 (P03) or GNRHR (P13). Here, SRD5A2 is linked to 46,XY disorder of sex development due to 5-alpha-reductase 2 deficiency.