Virological and clinical implication of core promoter C1752/V1753 and T1764/G1766 mutations in hepatitis B virus genotype D infection in Mongolia

Background and Aim: The aim of the present study was to reveal virological and clinical features of hepatitis B virus (HBV) genotype D infection. Methods: One hundred and twenty-two Mongolian chronic liver disease (CLD) patients infected with HBV were subjected for serological HBV-markers screening and HBV-enzyme immunoassay (EIA) genotyping. Nucleotide sequences were analyzed for 48 HBV/D strains (23 isolated from hepatocellular carcinoma (HCC) and 25 from CLD patients). Results: Prevalence of hepatitis B e antigen (HBeAg) positivity was low (25.9%) in young patients (<= 30 years old) indicating early HBeAg seroclearance in HBV/D carriers. The T1764/G1766 double mutation was the most common basal core promoter (BCP) mutation (29.2%) and was frequent in HBeAg-negative patients (39.3%). Patients harboring T1764/G1766 mutants exhibited lower HBV-DNA and HBV core antigen (HBcAg) levels than those with wild-type BCP strains (P = 0.024, 0.049, respectively). C1752 and/or V (not T) 1753 mutation was significantly prevalent in HCC patients (HCC vs CLD; 52.2% vs 20%, P = 0.033). T1762/A1764 mutation was detected in 75.0% of HCC patients with high viral load (>= 5 log copies/mL). Precore stop codon mutation A1896 was detected in (70.8%) of HBV/D-infected patients. Conclusions: In Mongolians infected with HBV/D, C1752 and/or V1753 mutation was associated with HCC.