PNPLA3 and fatty liver disease: The patatin-like phospholipase domain-containing protein 3 gene (PNPLA3), also known as adiponutrin, encodes a lipase enzyme expressed in adipocytes.9 The gene was first identified as a candidate for NAFLD susceptibility in a GWAS by Romeo et al,10 which found a significant association with the rs738409 polymorphism (not included in this review as fatty liver was assessed using 1H-MRI).