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 devel opment of both internal and external male structures in 46,XY individu als. This survey reports the analysis of 11 AIS subjects. The androgen receptor gene of these subjects was analyzed using polymerase chain r eaction (PCR)-single-strand conformation polymorphism analysis and seq uencing or sequencing of PCR-amplified androgen receptor gene fragment s alone. In total, 10 single base changes and one partial gene deletio n were detected. Seven single base changes resulted in an amino acid c hange, 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 wa s studied with respect to molecular mass after immunoprecipitation and SDS-PAGE. Two patients expressed a truncated receptor protein in agre ement with the established genomic mutation. Pedigree analysis was per formed to identify possible carriers for the syndrome in families of A IS patients using single-strand conformation polymorphism and restrict ion 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 mutat ions and to study the androgen receptor gene of family members of AIS- affected individuals.