Hepatic glycogenosis： An underdiagnosed complication ofdiabetes mellitus

Hepatic glycogenosis （HG） is characterized by excessiveglycogen accumulation in hepatocytes and representsa hepatic complication of diabetes that particularlyoccurs in patients with longstanding poorly controlledtype 1 diabetes （T1D）. HG has been reported tobe a very rare disease, although it is believed to beextremely underdiagnosed because it is not possibleto distinguish it from non-alcoholic fatty liver disease（NAFLD） unless a liver biopsy is performed. In contrastto HG, NAFLD is characterized by liver fat accumulationand is the more likely diagnosis for patients with type2 diabetes and metabolic syndrome. The pathogenesisof HG involves the concomitant presence of insulin andexcess glucose, which increases glycogen storage inthe liver. HG is characterized by a transient elevation inliver transaminases and hepatomegaly. Differentiatingbetween these two conditions is of the utmost importancebecause HG is a benign disease that is potentiallyreversible by improving glycemic control, whereas NAFLDcan progress to cirrhosis. Therefore, HG should besuspected when liver dysfunction occurs in patients withpoorly controlled T1D. The aim of this article is to reviewthe epidemiology, clinical characteristics, pathogenesisand histology of HG.