AimsThe 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.Methods222 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.ResultsHBV 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.ConclusionsHBV 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.

Accurate identification and characterization of infectious agent and its subtype is essential for efficient treatment of infectious diseases on a target population of patients. Comparative biology of microbial populations in vitro and in vivo can identify signatures that may be used to develop and improve diagnostic procedures. Here we report Genomic Signature Identification Tool (GSIT) a web based tool for identification and validation of genomic signatures in a group of similar DNA sequences of microorganisms. GSIT uses multiple sequence alignment to identify the unique base sites and scores them for inclusion as genomic signature for the particular strain. GSIT is a web based tool where the front-end in designed using HTML/CSS and Javascript, while back-end is run using CGI-Perl.AvailabilityThe server is freely available at the http://genome-sign.net/gsit