The androgen receptor gene is more than 90 kb long andcodes for a protein that has 3 major functional domains: theN-terminal domain, DNA-binding domain, and androgen-binding domain.The protein functions as a steroid-hormone activated transcriptionfactor. Upon binding the hormone ligand, the receptor dissociatesfrom accessory proteins, translocates into the nucleus, dimerizes,and then stimulates transcription of androgen responsive genes.This gene contains 2 polymorphic trinucleotide repeat segments thatencode polyglutamine and polyglycine tracts in the N-terminaltransactivation domain of its protein. Expansion of thepolyglutamine tract causes spinal bulbar muscular atrophy (Kennedydisease). Mutations in this gene are also associated with completeandrogen insensitivity (CAIS). Two alternatively spliced variantsencoding distinct isoforms have been described. [provided byRefSeq].