Hepatitis B Virus Genotype D is the Only Genotype Circulating in Iranian Chronic Carriers, the Unique Pattern of Genotypic Homogeneity

AIM:To characterize the hepatitis B virus surface protein genotypes and sequence variations among HBsAg positive chronic Iranian patients from different ethnic groups. METHOD: The surface genes from 312 patients were amplified and directly sequenced. RESULTS: All strains (100%) belonged to genotype D and subtypes ayw2. The average nucleotide mutation frequency was 0.91 (dN/ dS < 1.0), indicated negative selection. There was no significant correlation between HBV DNA and ALT levels and the occurrence of amino acid substitutions. However, in terms of HBeAg/AntiHBe status, the association between both groups for silent nucleotide mutation was strong, indicating selection bias on missense mutations. A higher number of amino acid mutations was found in anti-HBe positive versus HBeAg positive patients CONCLUSION:The uniqueness pattern of HBV genetics hemogeniety together with the low mutational frequency indicated that HBV has introduced to Iran recently and isolation of people in the absence of intermixing with other genotypes led to a homologous pattern.

HBV genotype D; HBV genotypes evolution; HBV surface mutations