Click here to view fulltext PDF

Permanent link:
https://www.ias.ac.in/article/fulltext/jgen/086/03/0195-0201

Hepatitis B virus (HBV); hepatitis B surface antigen; genotype 𝐷; 𝑆 gene region; mutation.

The 𝑆 gene region of the hepatitis B virus (HBV) is responsible for the expression of surface antigens and includes the ‘a’-determinant region. Thus, mutation(s) in this region would afford HBV variants a distinct survival advantage, permitting the mutant virus to escape from the immune system. The aim of this study was to search for mutations of the 𝑆 gene region in different patient groups infected with genotype 𝐷 variants of HBV, and to analyse the biological significance of these mutations. Moreover, we investigated 𝑆 gene mutation inductance among family members. Forty HBV-DNA-positive patients were determined among 132 hepatitis B surface antigen (HbsAg) carriers by the first stage of seminested PCR. Genotypes and subtypes were established by sequencing of the amplified S gene regions. Variants were compared with original sequences of these serotypes, and mutations were identified. All variants were designated as genotype 𝐷 and subtype ayw3. Ten kinds of point mutations were identified within the 𝑆 region. The highest rates of mutation were found in chronic hepatitis patients and their family members. The amino acid mutations 125 (M → T) and 127 (T → P) were found on the first loop of ‘a’-determinant. The other consequence was mutation inductance in a family member. We found some mutations in the S gene region known to be stable and observed that some of these mutations affected 𝑆 gene expression.

Mehmet Özaslan¹ Ersan Özaslan² Arzu Barsgan¹ Mehmet Koruk³

1. Department of Biology, University of Gaziantep, 27310/ Gaziantep, Turkey
2. Department of Gastroenterology, Ankara Numune Education and Training Hospital, 06100 / Ankara, Turkey
3. Department of Gastroenterology, University of Gaziantep, 27310/ Gaziantep, Turkey

Published

December 2007

Manuscript received

17 May 2006