AR and Kennedy disease: Although SBMA patients frequently exhibit signs of partial androgen insensitivity, including gynecomastia, testicular atrophy, and infertility, such noted partial loss of AR function does not explain the mechanism for SBMA neuromuscular symptoms (Pinsky et al., 1992); rather, these symptoms in SBMA result primarily from mutant AR proteotoxicity (Merry et al., 1998; Katsuno et al., 2002).