Precore and basal core promoter hepatitis B virus (HBV) variants are present from a young age and differ across HBV genotypes Daryl T Y Lau
1, Lilia Ganova-Raeva
2, Junyao Wang
3, Douglas Mogul
4, Raymond T Chung
5, Mauricio Lisker-Melman
6, Kyong-Mi Chang
7, Obaid S Shaikh
8, Harry L A Janssen
9, Abdus S Wahed
3, Anna S Lok
10, Hepatitis B Research Network
Collaborators, Affiliations
Abstract Background: HBV precore (PC) and dual basal core promoter (BCP) mutations halt and downregulate HBeAg production respectively. PC mutation is rarely associated with HBV genotype A. We sought to examine the association of these variants with HBV genotypes, age and HBeAg status in a racially diverse population in North America.
Methods: Prospective study included 1036 (808 adults, 228 children) participants in the Hepatitis B Research Network. PC and BCP variants were determined by Sanger sequencing and dominant HBV species (>50%) were reported.
Results: Median age was 36.3 years (range 2-80), 44.6% HBeAg(+), 74.2% Asians, 13.3% black and 9.7% white. The dominant PC variant was present in 29.4% participants including 20 with sub-genotype A1 or A2. 17/20 participants with genotype A and PC had a compensatory C1858T mutation. In the HBeAg(+) cohort, the prevalence of PC and/or BCP variants increased from 14.4% in the first 2 decades to 51% after 40 years of age. Among those aged 2-18, 52% and 83% with dominant PC and BCP variants were HBeAg(+) compared to 3.8% and 29% in the >40 years age group. HBeAg clearance rates were significantly higher for those with dominant PC or BCP variants, 24.4 and 15.0 per 100 person-years compared to 6.0 in WT HBV (p <0.0001).
Conclusions: PC variants can be present in HBV genotype A and are usually associated with C1858T that preserves the pregenome encapsidation sequence. Selection of PC and BCP variants occurred at a young age with increasing prevalence across age groups. HBeAg(+) participants with dominant PC and BCP variants progressed to the HBeAg(-) phase of chronic HBV infection significantly faster. This finding has potential clinical and therapeutic implications.
Keywords: Basal Core Promoter mutations; HBeAg; Precore mutation; chronic HBV infection; genotypes.
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