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Published on: February 1, 2017
Mutation analysis of hepatitis B virus promoters in chronically infected children
1Department of Biochemistry, School of Medicine, Korea University, Seoul, Korea.
Insights
Hepatitis B virus (HBV) in children often stems from mothers, with viral sequences mirroring maternal strains. Child-specific mutations may link to elevated liver enzymes and disease severity.
Area of Science:
- Hepatology
- Virology
- Pediatric Infectious Diseases
Background:
- Hepatitis B virus (HBV) infection in early childhood is a major cause of chronic hepatitis, liver cirrhosis, and hepatic carcinoma.
- Despite immunization, vertical transmission of HBV from mothers to children persists in Korea.
- Understanding childhood HBV infection dynamics is crucial for public health strategies.
Purpose of the Study:
- To analyze HBV promoter sequences in chronically infected children in Korea.
- To investigate the origin and characteristics of HBV variants in childhood infections.
- To explore correlations between HBV mutations, disease severity, and host-specific factors.
Main Methods:
- Analysis of four HBV promoter sequences from the sera of chronically infected children.
- Comparison of viral sequences between infected children and their mothers.
- Correlation analysis of promoter mutations with disease severity (ALT/AST levels) and age.
Main Results:
- Children harbored diverse HBV variants, similar to adults, but with rare deletion mutations.
- Dominant viral sequences in children were highly similar to their mothers', suggesting vertical transmission.
- Mutations in X, S1, and S2/S promoters showed no correlation with disease severity or age.
- Mutations in the C promoter correlated with disease severity but were not vertically transmitted.
- Elevated ALT/AST levels were associated with more child-specific HBV variants.
Conclusions:
- Vertical transmission is a primary route for childhood HBV infection in Korea.
- While maternal strains dominate, child-specific mutations may influence disease progression and clinical symptoms.
- C promoter mutations and host-specific viral evolution are potential factors in childhood HBV pathogenesis.
Abstract:
Hepatitis B viral (HBV) infection in early childhood is one of the leading causes of chronic hepatitis and liver cirrhosis that eventually lead to hepatic carcinoma. Despite the nationwide immunization programs to curtail the vertical transmission of HBV, childhood HBV infection through mothers is still occurring in Korea. As one of the efforts to understand the childhood HBV infection in Korea, four HBV promoter sequences in the sera of the chronically infected children were analyzed. Children harbored diverse viral variants as most of the chronically infected adult patients, but the deletion mutations were rare. The dominant viral sequences in the children were highly similar to the ones in the respective mothers, indicating that the maternal viruses were most likely transmitted to the children. The mutations in X, S1, S2/S promoters did not seem to show any correlation to the severity of the disease nor ages of the children. The mutations that showed some correlation to the severity of the disease were the mutations in C promoter, but the mutations did not seem to be vertically transmitted. Finally, the children with the elevated ALT/AST levels tended to have more child-specific variants suggesting that the accumulation of host-specific mutations might be associated with the development of clinical symptoms.
