Men with a mutation in AR(CAG)n (where n refers to the number of CAG repeats, n ​> ​38) manifest Kennedy’s disease or spinobulbar muscular atrophy (La Spada et al., 1991, 1992), while low n alleles have been associated with risk for prostate cancer and benign prostatic hyperplasia (Giovannucci et al., 1999; Kumar et al., 2011; Qin et al., 2016). The gene discussed is AR; the disease is Kennedy disease.