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World J Gastroenterol. Mar 21, 2014; 20(11): 2927-2940
Published online Mar 21, 2014. doi: 10.3748/wjg.v20.i11.2927
Hepatitis C virus genotype 6: Virology, epidemiology, genetic variation and clinical implication
Vo Duy Thong, Srunthron Akkarathamrongsin, Kittiyod Poovorawan, Pisit Tangkijvanich, Yong Poovorawan
Vo Duy Thong, Srunthron Akkarathamrongsin, Yong Poovorawan, Center of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
Kittiyod Poovorawan, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
Pisit Tangkijvanich, Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
Author contributions: Thong VD, Tangkijvanich P and Poovorawan Y designed research, reviewed all references and documents; Akkarathamrongsin S, Poovorawan K analyzed data; Thong VD, Tangkijvanich P and Poovorawan Y wrote paper. All authors reviewed and approved the final version.
Supported by Research Unit of Hepatitis and Liver Cancer, Chulalongkorn University; The Scholarship Program for Neighboring Countries, Chulalongkorn University; The Higher Education Research Promotion and National Research University Project of Thailand, HR1155A-55; Thailand Research Fund, DPG5480002, BRG5580005; Office of the Commission on Higher Education; Center of Excellence in Clinical Virology, Chulalongkorn University; Integrated Innovation Academic Center IIAC Chulalongkorn University Centenary Academic Development Project, CU56-HR01); the Ratchadaphiseksomphot Endowment Fund of Chulalongkorn University, RES560530093; and King Chulalongkorn Memorial Hospital
Correspondence to: Yong Poovorawan, MD, Professor, Center of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand. yong.p@chula.ac.th
Telephone: +66-2256-4909 Fax: +66-2256-4929
Received: September 24, 2013
Revised: January 6, 2014
Accepted: January 19, 2014
Published online: March 21, 2014
Processing time: 174 Days and 22.1 Hours
Abstract

Hepatitis C virus (HCV) is a serious public health problem affecting 170 million carriers worldwide. It is a leading cause of chronic hepatitis, cirrhosis, and liver cancer and is the primary cause for liver transplantation worldwide. HCV genotype 6 (HCV-6) is restricted to South China, South-East Asia, and it is also occasionally found in migrant patients from endemic countries. HCV-6 has considerable genetic diversity with 23 subtypes (a to w). Although direct sequencing followed by phylogenetic analysis is the gold standard for HCV-6 genotyping and subtyping, there are also now rapid genotyping tests available such as the reverse hybridization line probe assay (INNO-LiPA II; Innogenetics, Zwijnaarde, Belgium). HCV-6 patients present with similar clinical manifestations as patients infected with other genotypes. Based on current evidence, the optimal treatment duration of HCV-6 with pegylated interferon/ribavirin should be 48 wk, although a shortened treatment duration of 24 wk could be sufficient in patients with low pretreatment viral load who achieve rapid virological response. In addition, the development of direct-acting antiviral agents is ongoing, and they give high response rate when combined with standard therapy. Herein, we review the epidemiology, classification, diagnosis and treatment as it pertain to HCV-6.

Keywords: Hepatitis C virus; Genotype 6; Epidemiology; Clinical; Treatment

Core tip: Hepatitis C virus (HCV) genotype 6 is restricted to South China, South-East Asia, and it is occasionally found in migrant patients from endemic countries. Treatment response rates are lower than those of genotype 3 but higher than those of genotype 1. Based on current evidence, the optimal treatment duration of HCV-6 should be 48 wk. Shortened treatment duration of 24 wk could be sufficient in patients with low pretreatment viral load who achieve rapid virological response. The development of direct-acting antiviral agents is ongoing, and they give high response rate when combined with standard therapy. We review the epidemiology, classification, diagnosis and treatment.