6428 Update on Genetic F6428 actors of Nonalcoholic Fatty Liver Disease

Abstract Disclosure: H.M. Heshmati: None. Background: Nonalcoholic fatty liver disease (NAFLD) is a pandemic with a prevalence of 25% among the adult population worldwide. NAFLD is a spectrum of liver disorders ranging from simple steatosis to nonalcoholic steatohepatitis (NASH). NASH can progress to cirrhosis and hepatocellular cancer. The pathogenesis of NAFLD is complex and multifactorial, involving metabolic, epigenetic, and genetic factors. Several medical conditions (e.g., obesity, type 2 diabetes, inflammation, insulin resistance, disrupted gut microbiome, and impaired intestinal barrier function) are important risk factors associated with and/or contributing to NAFLD. This review presents an update on the genetic factors of NAFLD identified by the genome-wide association studies (GWAS). Methods: A systematic search of literature was conducted using the search terms nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, cirrhosis, hepatocellular cancer, obesity, type 2 diabetes, epigenetics, and genetics. Results: Evidence for the contribution of genetic factors to NAFLD is further emphasized by the ethnic differences in the prevalence of NAFLD (e.g., higher prevalence among Hispanic American compared to African American adults). Based on the results of the GWAS, several genetic modifiers are relevant to NAFLD development and progression. They include variations in patatin-like phospholipase domain-containing protein 3 (PNPLA3), transmembrane 6 superfamily 2 (TM6SF2), membrane-bound O-acyltransferase domain-containing protein 7 (MBOAT7), glucokinase regulatory protein (GCKR), programmed cell death protein 1 (PDCD1), and hydroxysteroid 17β-dehydrogenase 13 (HSD17B13) genes (non-exhaustive list). These genetic modifiers interact with the metabolic and epigenetic factors for the development and progression of NAFLD and are responsible for the variability in the severity of NAFLD. The PNPLA3 gene variant (rs738409), which is the first and the best validated genetic modifier, is associated with a high risk of development and progression of NAFLD. The PDCD1 gene variant (rs7421861) is independently associated with hepatocellular cancer development. In contrast, the HSD17B13 gene variant (rs72613567) may have a protective effect for NAFLD risk. Conclusion: NAFLD is a multifactorial condition with a complex pathogenesis involving the interactions between metabolic, epigenetic, and genetic factors. The prevalence and risk of NAFLD differ across popu