Mutations in the basic core promoter region of hepatitis B virus. Relationship with precore variants and HBV genotypes in a Spanish population of HBV carriers

Background/Aims: To determine the prevalence and significance of hepatitis B virus (HBV) basic core promoter (BCP) mutations and to establish their relationship with precore (preC) mutations, HBV genotypes and HBV-DNA levels. Methods: BGP and preC mutations and genotypes were determined by sequencing. Results: Genomic analysis was performed in 129 (71%) of 182 patients. BCP mutations were detected in 83% of 18 HBeAg-negative (e-) chronic hepatitis B (CHB) patients with fluctuating ALT levels, and in 76% of 58 e- CHB with elevated ALT. The prevalence was lower and similar, 55% in 30 HBeAg-positive CHB (e+ CHB) with elevated ALT and in 23 e- inactive carriers. Frequency of preC mutations was higher in e- CHB (80%) than in e- inactive carriers (65%). Among e- CHB, patients with elevated ALT and preC mutations at nt 1896 showed highest HBV-DNA, regardless of BCP mutations. BCP mutations were similar in genotypes A and D, while preC mutations were most common in genotype D (82 vs. 40%). Simultaneous presence of the main BCP (1762, 1764) and preC (1896, 1899) mutations was associated with the degree of histological injury. Conclusions: Combined BCP and preC mutational and genotype analysis provides clinically relevant information in the study of HBV infection. (C) 2003 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.