ABO and polycystic ovary syndrome: Total BCAA levels significantly differed between PCOS and the control group in the AbO+ subgroup (558.13 ± 100.51 vs. 514.22 ± 79.76 nmol/mL; p < 0.05) and concentrations of all the analyzed AAs were higher in PCOS patients (VAL 343.48 ± 65.69 vs. 314.29 ± 52.68 nmol/mL, p < 0.001; LEU 136.09 ± 22.83 vs. 126.41 ± 17.83 nmol/mL, p < 0.001; ILE 80.66 ± 16.26 vs. 72.79 ± 13.59 nmol/mL, p < 0.001).