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[The point mutation of pre-C region HBV-DNA in sera from chronic hepatitis B]
H Miyakawa1, K Abe, H Nakamura
14th Department of Internal Medicine, Teikyo University, School of Medicine.
Insights
A specific mutation in the Hepatitis B virus (HBV) Pre-C region, creating a stop codon, is linked to HBeAg-negative chronic hepatitis B. This viral mutation may explain fluctuating liver enzyme levels in these patients.
Area of Science:
- Hepatology
- Virology
- Molecular Biology
Background:
- Chronic hepatitis B (CHB) is a significant global health concern.
- Hepatitis B e antigen (HBeAg) serostatus is a key indicator in CHB management.
- Understanding HBV genetic variations is crucial for disease pathogenesis.
Observation:
- The study analyzed the HBV-DNA Pre-C region in 39 CHB patients.
- Polymerase chain reaction and direct sequencing were used to identify mutations.
- A specific Pre-C region stop codon mutation was investigated in relation to HBeAg status.
Findings:
- In HBeAg-positive patients (n=22), the Pre-C stop codon mutation was rare (1 case).
- In HBeAg-negative patients (n=17), the mutation was found in 6 cases (35%).
- These 6 HBeAg-negative cases exhibited fluctuating alanine aminotransferase (ALT) and DNA-polymerase levels.
Implications:
- The Pre-C stop codon mutation in HBV-DNA may be a primary cause of HBeAg-negative CHB.
- This mutation could explain the fluctuating ALT and DNA-polymerase levels observed in some HBeAg-negative patients.
- Identifying this mutation may aid in diagnosing and managing specific CHB patient cohorts.
Abstract:
To clarify the relationship between a point mutation of HBV-DNA Pre-C region and the serological feature of chronic hepatitis B, we determined the Pre-C region sequence of HBV-DNA obtained sera of 39 patients with chronic hepatitis B. The screening of the gene arrangement of Pre-C region of HBV-DNA was performed by a direct sequence method amplifying HBV-DNA by polymerase chain reaction methods. In 22 of HBeAg positive cases, a mutant type (the 28th codon changed from TGA to TAG: stop codon) was found in only one case. The other hand, In 17 of HBeAg negative cases, it was found in 6 cases with fluctuating ALT and DNA-polymerase levels. We concluded that mutant viral infections could be the main cause of HBeAg negative cases with fluctuating ALT and DNA-polymerase levels.