Hepatitis B (HBV) and Hepatitis D (HDV) is a confronting health issue in Pakistan with the number of individuals infected with HDV is not showing any decline. Prevalence of coinfection of HDV/HBV is about 16 – 57% in Pakistan. HDV being a satellite virus of HBV, replicates only in the presence of HBV. Compared to chronic carrier state of HBV alone, the HBV-HDV coinfection or superinfection are more susceptible to result in hepatocellular carcinoma (HCC), causing threefold increase in fatality. HDV has been classified into eight distinct clades or genotypes with clade I being predominant in Pakistan. Genotyping of viral infection is a routine diagnosis process as different clades have their own pattern and progression of disease hence information about the genotype of an infection helps in the prognosis of the disease. Conventionally, genotyping was done by RFLP analysis of the R0 region of the HDV but recently, sequencing and phylogenetic analysis of HDAg gene is considered a better method for genotyping. Phylogenetic analysis of nucleotide sequences of the Hepatitis Delta Antigen (HDAg) R0 region of twelve isolates from a gastroenterology treatment center in Karachi revealed presence a single genotype (HDV-1) with clustering of strains into three subgroups
