Mendonca et al. (1994) described an apparently autosomal recessive form of gonadal agenesis in 2 agonadic sisters, one with a 46,XY and the other with a 46,XX karyotype, and both with normal female external genitalia and hypoplastic mullerian ... Mendonca et al. (1994) described an apparently autosomal recessive form of gonadal agenesis in 2 agonadic sisters, one with a 46,XY and the other with a 46,XX karyotype, and both with normal female external genitalia and hypoplastic mullerian derivatives; the parents were consanguineous. Using PCR amplification, Southern hybridization, and denaturing gradient gel electrophoresis (DGGE), they found that the XY patient had no mutations in the conserved sequence of the SRY gene (480000), whereas her XX affected sister was SRY-negative. Mendonca et al. (1994) considered this to be the first report of XY and XX sibs with gonadal agenesis without other somatic abnormalities. Granat et al. (1983) had described two 46,XX sisters with gonadal dysgenesis who had a 46,XY azoospermic brother; a gene mutation in this family probably affected gonadal development at a later stage.