Since mouse Dmrt1 has been implicated in testicular differentiation [11], and intragenic deletions of human DMRT1 have been identified in 46, XY patients with gonadal dysgenesis [6], [12], it appears that DSD in case 1 results from haploinsufficiency of DMRT1. These data argue for the assumption that heterozygous deletions involving the coding exons and/or the upstream region of DMRT1 account for a substantial part of the etiology of complete and partial gonadal dysgenesis in individuals with 46, XY karyotype [6], [12], [13], [14]. This evidence concerns the gene DMRT1 and gonadal dysgenesis.