A practical approach to the detection of androgen receptor gene mutations and pedigree analysis in families with x-linked androgen insensitivity.

Androgen insensitivity syndrome (AIS) is an X-linked disorder in which defects in the androgen receptor gene have prevented the normal development of both internal and external male structures in 46,XY individuals. This survey reports the analysis of 11 AIS subjects. The androgen receptor gene of these subjects was analyzed using polymerase chain reaction (PCR)-single-strand conformation polymorphism analysis and sequencing or sequencing of PCR-amplified androgen receptor gene fragments alone. In total, 10 single base changes and one partial gene deletion were detected. Seven single base changes resulted in an amino acid change, one resulted in the introduction of a premature stop codon, one event represented a single base insertion resulting in a frame-shift, and one single base change affected a donor splice site. The androgen receptor protein in genital skin fibroblasts from several patients was studied with respect to molecular mass after immunoprecipitation and SDS-PAGE. Two patients expressed a truncated receptor protein in agreement with the established genomic mutation. Pedigree analysis was performed to identify possible carriers for the syndrome in families of AIS patients using single-strand conformation polymorphism and restriction site analysis of PCR products. In one case, the polymorphic (CAG)n(CAA) repeat in exon 1 encoding a polyglutamine stretch was used to identify the mutant allele in a family with X-linked partial androgen insensitivity before the identification of the actual genomic mutation. PCR-single-strand conformation polymorphism analysis proved to be a fast and reliable technique to screen for androgen receptor gene mutations and to study the androgen receptor gene of family members of AIS-affected individuals.