AR gene encodes androgen receptor protein (AR). It is a nuclear transcription factor which is activated by binding to the male sex steroids (the androgen hormones) and helps direct the development of male sexual characteristics.
More than 300 mutations in the AR gene have been identified in patients with androgen insensitivity syndrome. It was also found at least 85 mutations in the AR gene have been associated with prostate cancer. Almost all of these mutations are somatic. Moreover, it was found that polymorphisms in the AR gene are also associated with androgenetic alopecia.