%0 Journal Article
%T Hepatitis B virus subgenotypes D1 and D3 are prevalent in Pakistan
%A Saeeda Baig
%A Anwar Siddiqui
%A Runu Chakravarty
%A Tariq Moatter
%J BMC Research Notes
%D 2009
%I BioMed Central
%R 10.1186/1756-0500-2-1
%X to confirm specificity of PCR typing, phylogenetic analysis of the pre-S1 region and the divergence was studied through 13 sequences of 362 bp (accession number EF432765 ¨C EF432777). A total of 315 serum samples, selected from HBsAg positive patients representing the major ethnic groups, residing in Karachi, Sindh were tested for genotyping. Genotype D (219/315) was found to be the most prevalent (70%) amongst our patients. The rest of the genotypes A and a mixture of A and D (AD) were distributed as 20%, and 10% respectively. Phylogenetic tree demonstrated clustering of 11 samples with subgenotype D1 sequences and the remaining two strains on a branch within D3 samples. All samples intermixed with strains from other countries and were found to be closely related to Indian, Iranian and Egyptian HBV strains with 98.7 ¨C 99.0% homology.This study confirms the predominance of genotype D in southeastern Asia and presence of subgenotypes DI and D3 in the Pakistani infected patients. More studies are required to investigate the reason for fewer inclusions of D3 compared to the D1 in Pakistani HBV strains.The structural and functional differences between HBV genotypes are the mainstay to severity, complications, treatment and possibly vaccination against the virus. Subgenotypes have been identified in different HBV genotypes on the basis of a > 4% (but < 8%) difference in the complete nucleotide sequences [1]. The phylogenetic method, a reliable tool to study the divergence in the HBV, are now being utilized to elucidate the history and origin of HBV genome scattered geographically around the world [2]. It has become well known that the genotypes/sub-genotypes vary in the geographical areas and correlate strongly with ethnicity [3]. Pakistan is one of the intermediate HBV endemic countries having distinct multiethnic populations. However, sufficient information on the molecular epidemiology of HBV is not available. There is no data on subgenotypes and their recombination or
%U http://www.biomedcentral.com/1756-0500/2/1