Distribution of hepatitis C virus genotypes in patients with chronic hepatitis C infection in Western Turkey.

OBJECTIVE: The primary aim of this study was to determine the recent distribution of various genotypes of hepatitis C virus (HCV) in patients with chronic HCV infection in Western Turkey. Additional objectives were to determine whether there are any associations of genotype with gender and age, and to determine the nucleotide similarities and risk factors of non-1 HCV genotypes. METHODS: Serum samples from 345 patients (176 male, 169 female; mean age 53.3+/-12.7 years, range 10-81 years) with chronic HCV infection were analyzed in this study. Viral genotypes were determined by a restriction fragment length polymorphism (RFLP)-based in-house assay. To confirm genotypes for the samples with band patterns other than genotype 1, the 5' UTR was amplified and sequenced. RESULTS: Genotype 1 was observed in 335 of the 345 patients (97.1%). Of these, 34 patients showed infection with subtype 1a (9.9%) and 301 with subtype 1b (87.2%). Genotypes 2, 3, and 4 were determined in 0.9%, 1.4%, and 0.6% of the patients, respectively. Patients infected with type 1 were significantly older than patients infected with non-1 genotypes; however no significant differences were recorded in gender distribution. CONCLUSIONS: Genotypes other than genotype 1 are quite rare; these are possibly acquired in other countries. Turkish patients with chronic hepatitis C still represent a rather homogenous group with genotypic diversity encountered rarely.