Background: The aim of this study was to determine the frequency of the rs738409 polymorphism in the patatin-like phospholipase domain containing 3 (PNPLA3) gene in patients with polycystic ovary syndrome (PCOS) and its impact on nonalcoholic fatty liver disease (NAFLD) risk and severity. This evidence concerns the gene PNPLA3 and polycystic ovary syndrome.