In women with PCOS, one SNP in DKK1 (rs1569198) was associated with total testosterone, with major A allele carriers having increased testosterone levels (AA/AG: 2.74 (1.21) vs. GG: 2.36 (0.90) nmol/l; P = 0.0035). Here, DKK1 is linked to polycystic ovary syndrome.