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Basic Characteristics of Mutations
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Mutation Site
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P53R |
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Mutation Site Sentence
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Table2 |
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Mutation Level
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Amino acid level |
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Mutation Type
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Nonsynonymous substitution |
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Gene/Protein/Region
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PreS1 |
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Standardized Encoding Gene
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S
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Genotype/Subtype
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B;C |
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Viral Reference
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X02763
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Functional Impact and Mechanisms
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Disease
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Hepatitis B, Chronic
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Immune
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- |
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Target Gene
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-
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Clinical and Epidemiological Correlations
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Clinical Information
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Y |
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Treatment
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- |
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Location
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- |
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Literature Information
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PMID
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17258721
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Title
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Identification of a hepatitis B virus S gene mutant in lamivudine-treated patients experiencing HBsAg seroclearance
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Author
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Hsu CW,Yeh CT,Chang ML,Liaw YF
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Journal
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Gastroenterology
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Journal Info
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2007 Feb;132(2):543-50
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Abstract
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BACKGROUND & AIMS: Seroclearance of hepatitis B virus (HBV) surface antigen (HBsAg) is a rare event in chronic hepatitis B patients receiving lamivudine therapy. It is generally believed to be a benevolent sign, implicating clearance of viremia. The aim of this study is to examine the authenticity of this dogma. METHODS: In a 5-year period, 11 patients treated with lamivudine experienced seroclearance of HBsAg. The clinical data were examined. The HBV S gene sequences derived from the patient's serum samples before and after seroclearance of HBsAg were analyzed. RESULTS: Serum HBV-DNA could be detected by nested polymerase chain reaction (PCR) in all 11 patients, by 1-step PCR in 8, and by Cobas Amplicor HBV-DNA test (>200 copies/mL) in 5. A mutation hot spot, P120A in the S gene, was identified in 6 of the 11 patients. Site-directed mutagenesis experiments indicated that the Ausria-II RIA test failed to detect this mutant. Decreased sensitivity of detection was also observed when other monoclonal antibodies were applied. CONCLUSIONS: Seroclearance of HBsAg during lamivudine therapy may not indicate viral clearance. Specifically, it may be caused by a point mutation in the S gene, which results in detection failure. In such patients, further verification and follow-up using a sensitive HBV-DNA test are advised.
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Sequence Data
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-
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