Relation between hepatitis B virus genotypes and gene mutation of basic core promoter in Li nationality

Objective To investigate the relation between hepatitis B virus(HBV) genotypes and the double mutation of A-to-T nucleotide(nt) 1762 and G-to-A nt 1764 in basic core promoter(BCP T1762/A1764) in patients of the Li nationality. Methods Subjects were 125 HBV DNA positive patients that belong to the Li nationality on Hainan Island. HBV DNA genotype was determined by real time fluorimetry polymerase chain reaction. BCP T1762/A1764 mutation was performed using the direct sequencing method. Results The prevalence rates of genotype B, genotype C, genotype D, genotype C and D mixed infection(genotype C + D) and genotype B and D mixed infection (genotype B + C) were 31.20%, 53.60%, 12.00%, 2.40% and 0.80% respectively. Mutation frequencies in patients infected with HBV genotype C(58.21%) were significantly higher than in those infected with other genotypes (P < 0.01). The serum viral load of the patients with genotype C(5.74±1.21) was also higher than that of those with genotype B(P < 0.01). Conclusion The major genotypes in the Li nationality were genotype C and genotype B. The infection of genotype D and mixed infection also occurred in the Li nationality. Genotype C HBV has a higher replication rate, and the different degrees of pathogenecity among HBV genotypes may be related to BCP T1762/A1764 mutation frequency.