PNPLA3 and fatty liver disease: Genome-wide association studies suggest that variation in several genes [e.g., PNPLA3 (patatin-like phospholipase domain-containing protein 3), TM6SP2 (transmembrane 6 superfamily member 2), and FADS (fatty acid desaturase)] related to hepatic lipid metabolism are associated with increased hepatic steatosis in human NAFLD subjects (14–16).