Identification of a mutant allele of the androgen receptor gene in a family with androgen insensitivity syndrome: detection of carriers and prenatal diagnosis

We report the results of a molecular study of a
large family segregating the complete form of the
Androgen Insensitivity Syndrome (CAIS) in several
family members from three generations. We identified
the mutant allele by polymerase chain reaction (PCR)
amplification of the short tandem repeat (CAG)n, highly
polymorphic in the population, present in the first exon of
the androgen receptor (AR) gene. In this family four
different alleles were detected and one of these showed a
perfect segregation with the disease.
This study enabled us to identify the heterozygous
females in this family. We think that this simple, indirect
test, is also suitable for prenatal diagnosis of Morris’
syndrome when the mother is heterozygous for the size of
the short tandem repeat and one affected subject in the
family may be studied.