The mutant 148 Isoleucine to Methionine (I148M) protein variant in the patatin-like phospholipase domain-containing 3 (PNPLA3) gene results in a loss of function of the protein determining triglyceride retention in the hepatocytes, thus resulting in hepatic steatosis. The gene discussed is PNPLA3; the disease is Hepatic steatosis.