Abnormality of the DAX-1 gene accounts for many instances of congenital adrenal hypoplasia. In the present study, we performed molecular genetic analysis of DAX-1 in 4 unrelated Japanese patients with adrenal hypoplasia congenita and hypogonadotropic hypogonadism. A double-point mutation for V126M and W171X was identified in 1 family and a complex de novo insertion-deletion mutation was identified in a second. The DAX-1 gene was entirely deleted in a 3rd patient as well as in a 4th with the additional feature of glycerol kinase deficiency.