PLOD1 and polycystic ovary syndrome: Serum concentrations of T and LH were significantly higher in the PCOS group than the control group (n = 10, for the comparison of T, Z = -3.782, P < 0.001; for the comparison of LH, Z = -3.630, P < 0.001) (Fig. 1d,e), however, the concentrations of E2, FSH and insulin didn’t show significant difference between the two groups (n = 10, for the comparison of E2, t = − 1.639, P = 0.119; for the comparison of FSH, t = − 0.960, P = 0.350; for the comparison of insulin, t = 0.095, P = 0.926) (Fig. 1b, c, f).