Genetic analysis of a family with complete androgen insensitivity syndrome.

Androgen insensitivity causes impaired embryonic sex differentiation leading to developmental failure of normal male external genitalia in 46 XY genetic men. It results from diminished or absent biological actions of androgens, which is mediated by the androgen receptor (AR) in both the embryo and secondary sexual development. Mutations in the AR located on the X chromosome are responsible for the disease. Almost 70% of affected individuals inherit the mutation from their carrier mother. We hereby report a 10-year-old girl with all the characteristics of complete androgen insensitivity syndrome (CAIS). Similar scenario was observed in 3 maternal aunts, Sequencing of the AR gene in all the family members revealed C 2754 to T transition in exon 6. It was concluded that the C 2754 to T transition rendered the AR incapable of both ligand-binding and activating the transcription and was the cause of CAIS in the patient.