Complete androgen insensitivity syndrome due to X chromosome inversion: a clinical report.

We have studied a patient with complete androgen insensitivity syndrome (CAIS) and a 46, inv(X),Y karyotype. The patient's mother and maternal aunt also carry the inverted X, and the mother is phenotypically normal, with a 46, inv(X),X karyotype, while a maternal aunt has CAIS with a 46,inv(X),Y karyotype. Molecular cytogenetic studies demonstrate that one of the X inversion breakpoints occurs within Xq11.2-12, which is the locus for the androgen receptor. FISH analysis demonstrated that a BAC clone containing the androgen receptor gene was disrupted by the inversion. We therefore hypothesize that disruption of the androgen receptor gene causes CAIS in this patient. This is the first report of CAIS caused by a chromosome inversion.