Identification of a critical novel mutation in the exon 1 of androgen receptor gene in 2 brothers with complete androgen insensitivity syndrome

Complete androgen insensitivity syndrome is an X-linked inherited disorder caused by mutations in the androgen receptor (AR) gene. Using polymerase chain reaction single-strand DNA conformational polymorphism and DNA sequencing, we identified a novel nonsense mutation in exon 1 of the AR gene in 2 Iranian brothers with complete androgen insensitivity syndrome. Despite a normal 46,XY karyotype, testes, and normal to elevated plasma levels of testosterone, they were born with female external genitalia and phenotype. This new mutation, a T-to-A transversion in exon 1, causes amino acid change of tyrosine (TAT) to ochre stop codon (TAA) at position 514 of the AR polypeptide. The Y514X mutation is located in a region that is normally important for the formation and function of the hormone receptor complex. We conclude that the novel Y514X mutation in the androgen receptor is the cause of complete androgen insensitivity syndrome in this family.