FASN and fatty liver disease: For instance, both inflammation and insulin resistance can cause hepatic steatosis through increasing liver expression of genes for lipogenic enzymes such as acetyl-CoA carboxylase 1 (ACC1) and fatty acid synthase (FAS) and decreasing liver expression of genes for fatty acid oxidation including carnitine palmitoyltransferase 1a (CPT1a)11, 12, 13.