Genotype Distribution and 5′ UTR Nucleotide Changes in Hepatitis C Virus

Objective: HCV is a single-stranded RNA virus which has 9500 nucleotide. On the 3' and 5' ends of the genome, there are two untranslated regions (UTR) which are highly protected and which have 92% homology among various HCV types. 5' UTR is used for the genotype detection. In this study, genotype and nucleic acid changes in this region were analyzed. Material and Methods: In 51 patients diagnosed with HCV, HCV-RNA was isolated and purified from serum samples. The 341 nucleotide-long UTR region at the 5'end of the genome was sequenced and genotypes were detected. Nucleotide changes were analyzed with on-line BLAST program. Results: In 45 (88.2%) of 51 patients, genotype-1 (78.4% of all genotypes were 1b, 9.8% were la) was detected. In 41(80.4%) of the 51 sequences, nucleic acid changes were detected. These changes generally occurred as an insertion in codon 84; deletion in codon 43 and codon 46; transversion in codon 15, 17 and 18, and transition in codon 62. No significant relationship was found between viral load and nucleic acid changes. Conclusion: Although the 5'UTR region is a protected region, mutation can be observed, and the mutations may affect the genotype, viral load and treatment response. Therefore, further investigation is required in a large series.