title: Mutation profiling of the hepatitis B virus strains circulating in North Indian population.
abstract: OBJECTIVE
  The aim of this study was to investigate the genomic mutations in the circulating Hepatitis B virus strains causing infection in the Indian population. Further, we wanted to analyze the biological significance of these mutations in HBV mediated disease.
  
  
  METHODS
  222 HBsAg positive patients were enrolled in the study. The genotype and mutation profile was determined for the infecting HBV isolate by sequencing overlapping fragments. These sequences were analyzed by using different tools and compared with previously available HBV sequence information. Mutation Frequency Index (MFI) for the Genes and Diagnosis group was also calculated.
  
  
  RESULTS
  HBV Genotype D was found in 55% (n = 121) of the patient group and genotype A was found in 30% (n = 66) of samples. The majority (52%) of the HBV-infected individuals in the present study were HBeAg-negative in all the age groups studied. Spontaneous drug associated mutations implicated in resistance to antiviral therapy were also identified in about quarter of our patients, which is of therapeutic concern. The MFI approach used in the study indicated that Core peptide was the most conserved region in both genotypes and Surface peptide had highest mutation frequency. Few mutations in X gene (T36A and G50R) showed high frequency of association with HCC. A rare recombinant strain of HBV genotype A and D was also identified in the patient group.
  
  
  CONCLUSIONS
  HBV genotype D was found out to be most prevalent. More than half of the patients studied had HBeAg negative disease. Core region was found to be most conserved. Drug Associated mutations were detected in 22% of the patient group and T36A and G50R mutations in X gene were found to be associated with HCC.
authors.affiliation: Institute of Molecular Medicine, New Delhi, India; Amity Institute of Biotechnology, Amity University, Noida, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Tuteja
authors.affiliation: Institute of Molecular Medicine, New Delhi, India.
authors.forename: Abu Baker
authors.initials: AB
authors.lastname: Siddiqui
authors.affiliation: Department of Gastroenterology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Kaushal
authors.initials: K
authors.lastname: Madan
authors.affiliation: Department of Gastroenterology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Rohit
authors.initials: R
authors.lastname: Goyal
authors.affiliation: Department of Gastroenterology, All India Institute of Medical Sciences, New Delhi, India.
authors.lastname: Shalimar
authors.affiliation: Department of Statistics, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Vishnubhatla
authors.initials: V
authors.lastname: Sreenivas
authors.affiliation: Amity Institute of Biotechnology, Amity University, Noida, India.
authors.forename: Navkiran
authors.initials: N
authors.lastname: Kaur
authors.affiliation: Department of Pathology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Subrat K
authors.initials: SK
authors.lastname: Panda
authors.affiliation: Institute of Molecular Medicine, New Delhi, India.
authors.forename: Krishnamoorthy
authors.initials: K
authors.lastname: Narayanasamy
authors.affiliation: Institute of Molecular Medicine, New Delhi, India; Open Source Drug Discovery Unit, Council of Scientific & Industrial Research, New Delhi, India.
authors.forename: Swati
authors.initials: S
authors.lastname: Subodh
authors.affiliation: Department of Gastroenterology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Subrat K
authors.initials: SK
authors.lastname: Acharya
mesh_terms: D000328:Adult; D004279:DNA, Viral; D024882:Drug Resistance, Viral / Q000235:genetics; D005260:Female; D005814:Genes, Viral; D016679:Genome, Viral; D005838:Genotype; D006514:Hepatitis B Surface Antigens / Q000235:genetics; D006515:Hepatitis B virus / Q000187:drug effects / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000175:diagnosis / Q000821:virology*; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016865:Reassortant Viruses; D011995:Recombination, Genetic; D055815:Young Adult
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens