Variations and mutations in the hepatitis B virus genomeand their associations with clinical characteristics

Hepatitis B virus （HBV） infection is major global issue,because chronic HBV infection is strongly associatedwith liver cancer. HBV spread worldwide with variousmutations and variations. This variability, called quasispecies,is derived from no proof-reading capacity ofviral reverse transcriptase. So far, thousands of studiesreported that the variety of genome is closely related tothe geographic distribution and clinical characteristics.Recent technological advances including capillarysequencer and next generation sequencer have made ineasier to analyze mutations. The variety of HBV genomeis related to not only antigenicity of HBs-antigen but alsoresistance to antiviral therapies. Understanding of thesevariations is important for the development of diagnostictools and the appropriate therapy for chronic hepatitisB. In this review, recent publications in relation to HBVmutations and variations are updated and summarized.