IL17A and polycystic ovary syndrome: When using SNPs with a higher cut-off of significance P < 5 × 10–6, the SCGFb level and interleukin-4 (IL-4) level are inversely associated with PCOS (OR = 0.838, 95% CI = 0.712 – 0.986, P = 0.034 and OR = 0.637, 95% CI = 0.413 – 0.983, P = 0.042, respectively), whereas IL-17 and stromal-cell-derived factor 1 alpha (SDF1a) levels are associated with an increased risk of PCOS (OR = 1.794, 95% CI = 1.150 – 2.801, P = 0.010 and OR = 1.563, 95% CI = 1.055 – 2.315, P = 0.026, respectively) using IVW methods.