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Updated: Jun 3, 2026

Real-Time Polymerase Chain Reaction-Based Detection and Quantification of Hepatitis B Virus DNA
Published on: December 15, 2023
Genetic analysis of complement component 9 (C9) polymorphisms with clearance of hepatitis B virus infection
Joon Seol Bae1, Charisse Flerida A Pasaje, Byung Lae Park
1Laboratory of Genomic Diversity, Department of Life Science, Sogang University, Shinsu-dong, Mapo-gu, Seoul 121-742, Republic of Korea.
Background:
The complement component 9 (C9), a major cytolytic protein in the complement system, plays an important role in the immunological process. However, associations between genetic variations of the complement factor and chronic hepatitis B virus infection still need to be investigated.
Aims:
We hypothesized that genetic variations in the complement component 9 gene can influence the clearance of chronic hepatitis B virus infection, hepatocellular carcinoma occurrence, and onset age of hepatocellular carcinoma. To investigate the relationship between complement component 9 variations and these disease phenotypes, we performed a case-control association analysis in a Korean population.
Methods:
Genetic variations were identified through direct DNA sequencing and genotyped using TaqMan assay (n = 1,103). In order to investigate the relationship of complement component 9 with chronic hepatitis B virus clearance and hepatocellular carcinoma occurrence, differences in SNP and haplotype frequency distributions were analyzed using logistic and multiple regression analyses with adjusted age and gender as covariates.
Results:
Although +23189C>T polymorphism in exon 4 and C9_ht2 [T-G-C-A-C] were significantly associated with clearance of chronic hepatitis B virus infection and hepatocellular carcinoma occurrence, the association signals were not retained after multiple testing corrections.
Conclusions:
We conclude that variations in the complement component 9 gene are unlikely to influence clearance of chronic hepatitis B virus infection and hepatocellular carcinoma occurrence. Although this preliminary result provides meaningful information, further functional investigations in other genetic factors for pathway analyses are required.
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