Among the PCOS patients, the FGF21 concentrations were significantly higher in those with NAFLD, whereas a 1 pg/mL increase in the FGF21 concentration increased the odds of NAFLD by 1%, suggesting FGF21 as a potential biomarker for hepatic disease in females with PCOS in adolescence. The gene discussed is FGF21; the disease is polycystic ovary syndrome.