Genotype distribution and comparison of the putative envelope region of hepatitis C virus from Korean patients.

Comparative nucleotide sequence studies of the genomes of hepatitis C virus (HCV) revealed that there are at least 6 different genotypes of HCV. The prevalence of HCV genotypes among the patients with liver diseases in Korea was investigated using the polymerase chain reaction (PCR) for the NS5 region. In the 75 HCV RNA positive samples, two genotypes, type 1b and type 2a, were the major causative agents which accounted for 60% and 33% of infections respectively, while 7% could not be assigned a genotype by the methods used. The nucleotide sequences of cDNAs encoding the putative envelope proteins from 10 type 1b and 5 type 2a genotype samples were analyzed. Approximately 31-42% of the nucleotide sequences of type 1b samples examined differed from those of different genotypes. In the case of type 2a samples, 36-42% of the nucleotide sequences differed from those of different genotypes. The diversities of the amino acid sequences were the same or greater than those of the nucleotide sequences. Two hypervariable regions (HVR1 and HVR2) were recognized in both HCV genomes of genotypes 1b and 2a. However, the sequence divergence within the HVR2 region of genotype 2a was less than that of genotype 1b.