It is also different from acute exacerbation of CHB, which is defined as clinical symptoms along with an abrupt rise in serum ALT to a certain level, e.g. above 200 IU/L [31] or 500 IU/L [32], and only a small proportion of such patients develops fulminant hepatic failure that meets the criteria of HB-ACLF. The gene discussed is GPT; the disease is Fulminant hepatic failure.