PNPLA3 (Patatin-Like Phospholipase Domain Containing 3): PNPLA3 is a gene that encodes an enzyme known as adiponutrin or patatin-like phospholipase domain-containing protein 3. This enzyme plays a key role in lipid metabolism by hydrolyzing triglycerides in adipocytes. Variations in the PNPLA3 gene are linked to liver conditions, including non-alcoholic fatty liver disease (NAFLD).