AR and androgen insensitivity syndrome: Recently, several investigators have reported heterozygous loss-of-function mutations in the nuclear receptor subfamily five group A member 1 gene (NR5A1) in patients with clinical features of androgen insensitivity syndrome (AIS) but without androgen receptor gene (AR) mutations.2 Mutations in AR, which is located on chromosome Xq11-q12, is responsible for AIS.