Hepatitis B virus genotypes and mutations in the basal core promoter and pre-core/core in chronically infected patients in southern Brazil: a cross-sectional study of HBV genotypes and mutations in chronic carriers

• Published in: Revista da Sociedade Brasileira de Medicina Tropical
• Main Authors: Flávia Miryan Martins Almeida de Mello, Aline Satie Oba Kuniyoshi, André Fanhani Lopes, Michele Soares Gomes-Gouvêa, Dennis Armando Bertolini
• Format: Article in Journal/Newspaper
• Language: English
• Published: Sociedade Brasileira de Medicina Tropical (SBMT) 2014
• Subjects: HBV; Genotypes; Subgenotypes; Basal core promoter mutations; Precore/core mutations; Arctic medicine. Tropical medicine; RC955-962; Arctic
• Online Access: https://doi.org/10.1590/0037-8682-0158-2014; https://doaj.org/article/3eb975de2b4d4f639506d36618de9b9d

Introduction In Brazil, little data exist regarding the distribution of genotypes in relation to basal core promoter (BCP) and precore/core mutations among chronic hepatitis B virus (HBV) carriers from different regions of the country. The aim of this study was to identify HBV genotypes and the frequency of mutations at the BCP and precore/core region among the prevalent genotypes in chronic carriers from southern Brazil. Methods Nested-polymerase chain reaction (nested-PCR) products amplified from the S-polymerase gene, BCP and precore/core region from 54 samples were sequenced and analyzed. Results Phylogenetic analysis of the S-polymerase gene sequences showed that 66.7% (36/54) of the patients were infected with genotype D (D1, D2, D3), 25.9% (14/54) with genotype A (A1, A2), 5.6% (3/54) with subgenotype C2, and 2% (1/54) with genotype E. A comparison of virological characteristics showed significant differences between genotypes A, C and D. The comparison between HBeAg status and the G1896A stop codon mutation in patients with genotype D revealed a relationship between HBV G1896A precore mutants and genotype D and hepatitis B e antigen (HBeAg) seroconversion. Genotype D had a higher prevalence of the G1896A mutation and the presence of a thymine at position 1858. Genotype A was associated with a higher prevalence of the G1862T mutation and the presence of a cytosine at position 1858. Conclusions HBV genotype D (D3) is predominant in HBV chronic carriers from southern Brazil. The presence of mutations in the BCP and precore/core region was correlated with the HBV genotype and HBeAg negative status.