Natural history of NASH.

Non-alcoholic fatty liver disease (NAFLD) is the fastest growing cause of chronic liver disease worldwide. Although only a small proportion of NAFLD patients will progress to end-stage liver disease and death, the clinical burden of NAFLD is substantial due the sheer number of individuals affected worldwide. In fact, recent estimates suggest that 25% of the world have NAFLD, which is now one of the leading causes of cirrhosis and indications for liver transplantation. Although liver-related mortality is common, the most common cause of death in patients with NAFLD is related to cardiovascular diseases, followed by extra-hepatic cancers. There is a significant interindividual variability in the susceptibility to liver disease. The severity of metabolic alterations is the main risk factor for progressive NAFLD, but the qualitative components of diet, physical activity and genetic factors also play an important role. In particular, common variants in patatin-like phospholipase domain-containing 3 (PNPLA3), transmembrane 6 superfamily member 2 (TM6SF2), membrane bound O-acyl transferase 7 (MBOAT7) and glucokinase regulator (GCKR) have been shown to contribute to the full spectrum of NAFLD. In those at risk of a potentially progressive form of NAFLD or non-alcoholic steatohepatitis or in those with hepatic fibrosis, additional assessment must be made.