Epidemiological study of hepatitis B virus genotypes, core promoter and precore mutations of chronic hepatitis B infection in Hong Kong

Background/Aims: We conducted a population study to document the prevalence of hepatitis B virus (HBV) genotypes in Hong Kong. Methods: HBV genotypes, core promoter (CP) and precore mutations were determined in 776 asymptomatic patients. Results: 92.6% patients had single genotype [B (32.5%), C (62.5%)]. 99.1% of genotype B was subtype Ba. Patients with age <50 years had a lower prevalence of genotype B than patients with age >51 years (32.5% vs. 41%, respectively, P = 0.028). Compared to patients with genotype C, patients with genotype B had a higher cumulative rate (P = 0.018) and younger age (40.1 vs. 34.2 years, respectively, P = 0.018) of HBeAg seroconversion. There were no differences in the HBV DNA levels between patients with genotypes B and C, and with wild-type and mutants of CP and precore regions. By multivariate analysis, patients with genotype C and with CP mutations had higher alanine aminotransferase (ALT) levels. Conclusions: B and C were the two most common HBV genotypes in Hong Kong. The former had a higher chance of earlier HBeAg seroconversion and lower ALT levels. The prevalence of genotype B was lower in patients with age < 50, probably related to influx of immigrants from China since 1949. (C) 2004 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.