C601S mutation in the androgen receptor results in partial loss of androgen function

Abstract

The present study was undertaken on a case of partial androgen insensitivity syndrome to look at the etiology of the disorder. The patient exhibited a female phenotype despite 46,XY chromosome complement. Direct DNA sequencing of coding region of the androgen receptor gene in this case revealed a 2329G>C substitution (cDNA sequence reference) in exon 3 of the gene. The substitution resulted in replacement of Cys with Ser at codon 601 of the ligand-binding domain of the protein. Analyses on 200 control samples revealed absence of this substitution(s). In vitro assays were done using COS-1 cells. The mutation resulted in partial (~40%) loss of ligand-binding and significant (~70%) loss of downstream transactivation function. The mutation was absent in the controls. The findings are particularly interesting since another substitution at the same codon (TG̲C-TT̲C) has been reported in association with complete androgen insensitivity syndrome.