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Basic Characteristics of Mutations
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Mutation Site
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G149R |
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Mutation Site Sentence
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Site-directed mutagenesis experiments showed that secretion of HBsAg was not defective in the pre-S2 G149R mutant. |
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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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PreS2 |
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Standardized Encoding Gene
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S
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Genotype/Subtype
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- |
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Viral Reference
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-
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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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- |
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Treatment
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- |
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Location
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China |
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Literature Information
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PMID
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12974898
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Title
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Identification of a novel pre-S2 mutation in a subgroup of chronic carriers with spontaneous clearance of hepatitis B virus surface antigen
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Author
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Yeh CT,Chang MH,Lai HY,Chang ML,Chu CM,Liaw YF
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Journal
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Journal of gastroenterology and hepatology
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Journal Info
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2003 Oct;18(10):1129-38
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Abstract
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BACKGROUND AND AIM: The aim of the present study was to investigate whether spontaneous seroclearance of hepatitis B surface antigen (HBsAg) in patients with chronic hepatitis B could be attributed to the presence of pre-S/S gene mutations. METHODS: Of 34 hepatitis B virus (HBV) carriers who experienced spontaneous seroclearance of HBsAg, 30 were still seropositive for HBV DNA. The serum samples of these carriers were subjected to sequence analysis. RESULTS: A novel pre-S2 mutation, G149R, was found in nine (group I) but not in 17 (group II) patients carrying HBV DNA with intact pre-S/S reading frames. In the remaining four patients (group III), only aberrant pre-S/S transcripts were found in their sera. Distinct patterns of amino acid substitutions specific to group I and II patients were identified. Superinfection by hepatitis C or D virus occurred predominantly in group II patients (P = 0.019). Superinfection by HBV of a different genotype occurred predominantly in patients without hepatitis C or D virus superinfection (P = 0.013). Site-directed mutagenesis experiments showed that secretion of HBsAg was not defective in the pre-S2 G149R mutant. CONCLUSIONS: In a particular subgroup (group I) of patients, seroclearance of HBsAg was not caused by superinfection of other hepatitis viruses, nor was it caused by failure of HBsAg secretion or detection. Instead, a yet unrecognized mechanism associated with emergence of a novel pre-S2 mutation is responsible.
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Sequence Data
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-
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