Clinical significance of core gene mutations during the course of genotype C chronic hepatitis B virus infection

Background/Aims: The aim of this study was to investigate the association of HBV core gene mutations with disease severity in HBV-infected patients. Methodology: We included 249 genotype C HBV-infected patients: 39 asymptomatic carriers (AC), 68 with chronic hepatitis (CH), 75 with liver cirrhosis (LC), and 67 with HCC. HBV DNA was extracted from patient sera and the HBV core gene was analyzed by PCR and sequencing. Results: The overall frequency of a codon substitution, which was caused by a missense mutation in the HBV core region, was 4.5±9.0/patient. The codon substitutions were predominantly clustered in the mid-core regions; 22.3% of codon substitutions were found in codons 13, 87, 97 and 130. The rate of substitution for codon 13 was higher in CH and LC than in AC. For codons 87 and 130, AC had a lower substitution rate compared to the other 3 groups. The substitution rate for codon 97 was higher in CH and HCC than in AC. Conclusions: Core gene mutations were frequently detected during the course of chronic HBV infection, and some mutational hot spots were correlated with severe forms of disease. Thus, these mutations might play a pathophysiological role in the disease progression in HBV-infected patients.