FREM2 and disorder of sexual differentiation: The other three variants of AKR1C4, CYP17A1 or FREM2 genes were predicted to be disease-causing (Table 2) but mutations of CYP17A1 and FREM2 genes caused DSD in karyotypic men only when both alleles of those genes were mutated [19,20,21], therefore the heterozygous status of CYP17A1 and FREM2 variants in our patient make their contribution to the DSD phenotype unlikely.