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Updated: Feb 26, 2026
Detection of Low Copy Number Integrated Viral DNA Formed by In Vitro Hepatitis B Infection
Published on: November 7, 2018
Untypable genotype restriction patterns and surface gene variants of hepatitis B virus isolates
Michael O Baclig1, Karen G Reyes1, Veni R Liles1
1Research and BiotechnologySt. Luke's Medical Center-Quezon City, Philippines.
Insights
Accurate Hepatitis B virus (HBV) genotyping in the Philippines identified genotypes A, B, and C. DNA sequencing resolved untypable genotypes and detected crucial surface gene variants for better clinical management.
Area of Science:
- * Virology
- * Molecular Biology
- * Epidemiology
Background:
- * Chronic hepatitis B is a significant global health issue, contributing to cirrhosis and liver cancer.
- * Hepatitis B virus (HBV) genotyping is vital for effective clinical management and epidemiological research.
- * Understanding HBV genotype distribution is crucial for targeted public health interventions.
Purpose of the Study:
- * To determine the prevalence of circulating HBV genotypes in the Philippines.
- * To molecularly characterize HBV isolates that were untypable by traditional methods.
- * To identify variants in the HBV surface gene that may impact clinical outcomes.
Main Methods:
- * Restriction Fragment Length Polymorphism (RFLP) was used for initial HBV genotyping.
- * DNA sequencing and phylogenetic analysis were employed to resolve untypable genotypes.
- * Analysis of the S gene was conducted to detect variations and amino acid changes.
Main Results:
- * RFLP detected HBV genotypes A (76%), B (10%), and C (14%).
- * DNA sequencing identified HBV genotypes A (67%), B (11%), and C (22%) among previously untypable isolates.
- * 55% of sequenced isolates exhibited variations in the surface gene, leading to amino acid alterations.
Conclusions:
- * DNA sequencing and phylogenetic analysis are effective in resolving untypable HBV genotypes.
- * Accurate HBV genotyping and detection of surface gene variants are essential for optimal patient management.
- * This study provides critical data on HBV genotypes circulating in the Philippines, informing regional health strategies.
Abstract:
Chronic hepatitis B is a global health problem, and is one of the leading causes of cirrhosis and hepatocellular carcinoma. Hepatitis B virus (HBV) genotyping helps in decision making for clinical management of HBV infection, and is important for epidemiological studies. The objectives of this study were to investigate the distribution of HBV genotypes circulating in the Philippines; molecularly characterize untypable genotype restriction patterns; and analyze the presence of surface gene variants. HBV genotypes were determined by restriction fragment length polymorphism (RFLP) and DNA sequencing. Three genotypes, HBV A (76%; 73/96), HBV B (10%; 10/96) and HBV C (14%; 13/96) were detected by RFLP. Out of the 96 isolates, 9% were untypable by RFLP analysis. DNA sequencing followed by phylogenetic analysis revealed that these isolates belonged to HBV genotypes A (67%; 6/9), B (11%; 1/9) and C (22%; 2/9). Out of the 9 isolates, 55% showed single or multiple variations which resulted to amino acid changes. Overall, the identification of untypable genotype can be resolved by sequence and phylogenetic analysis of the S gene and this approach can also be used to detect single or multiple variants. Our findings underscore the importance of accurate genotyping and detection of surface gene variants by DNA sequencing for optimal clinical management.
