Abstract
BACKGROUND: Hepatitis C virus (HCV) has different genotypes throughout the world. Since the determination of which antiviral treatment to be applied is related to HCV genotypes, identification of an individual's HCV genotypes prior to antiviral therapy is critical. OBJECTIVES: The purpose of this study was to investigate the distribution of HCV genotypes in a large population of Iranian HCV infected patients. PATIENTS AND METHODS: Eleven thousand, five hundred and sixty one patients with chronic HCV infection which referred to hospitals related to the Tehran University of Medical Sciences and Tehran Hepatitis Center-Clinical Department of Baqiyatallah Research Center for Gastroeneterology and Liver Disease from March 2003 to December 2011 were enrolled. Following extraction of viral RNA of the serum, HCV-RNA was detected using reverse transcriptase-nested polymerase chain reaction (RT-nested PCR) and then HCV genotypes analyzed by restriction fragment length polymorphism (RFLP) assay. RESULTS: The mean age of patients was 37.6 ± 14.2 years (range: 1-87). The highest frequency was noted for subtype 1a (44.9%) followed by subtype 3a (39.6%), and 1b (11.3%). Mixed HCV genotypes were also found in 2.5% of the total cases. Subtype 1a was the most frequent genotype in patients over 40 years of age (46.1% versus 42.4%) and subtype 3a was the most frequent in patients under 40 years old (41.5% versus 38.9%). CONCLUSIONS: This study suggested that the dominant HCV subtype among Iranian patients was 1a followed by subtype 3a.