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World J Hepatol. Mar 27, 2015; 7(3): 583-592
Published online Mar 27, 2015. doi: 10.4254/wjh.v7.i3.583
Variations and mutations in the hepatitis B virus genome and their associations with clinical characteristics
Yoshihiko Yano, Takeshi Azuma, Yoshitake Hayashi
Yoshihiko Yano, Takeshi Azuma, Department of Gastroenterology, Kobe University Graduate School of Medicine, Kusunoki-cho, Kobe 650-0017, Japan
Yoshihiko Yano, Yoshitake Hayashi, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kusunoki-cho, Kobe 650-0017, Japan
Author contributions: Yano Y mainly contributed to this review; Azuma T and Hayashi Y contributed to critical revision and finalized the manuscript.
Supported by A Grant-in-Aid from the Japan Initiative for Global Research Network on Infectious Disease (J-GRID) Program of the Ministry of Education, Culture, Sports, Science and Technology, Japan; a SATREPS Grant from the Japan Science and Technology Agency and the Japan International Cooperation Agency; and by the Ministry of Health, Labour, and Welfare of Japan, No. H25-general-008.
Conflict-of-interest: None.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Yoshihiko Yano, MD, PhD, Center for Infectious Diseases, Graduate School of Medicine, Kobe University, 7-5-1 Kusunoki-cho, Chuo-Ku, Kobe 650-0017, Japan. yanoyo@med.kobe-u.ac.jp
Telephone: +81-78-3826305 Fax: +81-78-3826309
Received: August 28, 2014
Peer-review started: August 28, 2014
First decision: November 14, 2014
Revised: November 27, 2014
Accepted: December 29, 2014
Article in press: December 29, 2014
Published online: March 27, 2015
Abstract

Hepatitis B virus (HBV) infection is major global issue, because chronic HBV infection is strongly associated with liver cancer. HBV spread worldwide with various mutations and variations. This variability, called quasispecies, is derived from no proof-reading capacity of viral reverse transcriptase. So far, thousands of studies reported that the variety of genome is closely related to the geographic distribution and clinical characteristics. Recent technological advances including capillary sequencer and next generation sequencer have made in easier to analyze mutations. The variety of HBV genome is related to not only antigenicity of HBs-antigen but also resistance to antiviral therapies. Understanding of these variations is important for the development of diagnostic tools and the appropriate therapy for chronic hepatitis B. In this review, recent publications in relation to HBV mutations and variations are updated and summarized.

Keywords: Hepatitis B virus, Mutation, Quasispecies

Core tip: Hepatitis B virus infection is major global issue. HBV spread worldwide with various mutations and variations. So far, thousands of studies reported that the variety of genome is closely related to the geographic distribution and clinical characteristics. Recent technological advances have made in easier to analyze mutations. Understanding of these variations is important for the development of diagnostic tools and the appropriate therapy for chronic hepatitis B.