Prevelance of Common YMDD Motif Mutations in Long Term Treated Chronic HBV Infections in a Turkish Population

In the current study we aimed to show the common YMDD motif mutations in viral polymerase gene inchronic hepatitis B patients during lamivudine and adefovir therapy. Forty-one serum samples obtained fromchronic hepatitis B patients (24 male, 17 female; age range: 34-68 years) were included in the study. HBV-DNAwas extracted from the peripheral blood of the patients using an extraction kit (Invisorb, Instant Spin DNA/RNA Virus Mini Kit, Germany). A line probe assay and direct sequencing analyses (INNO-LIPA HBV DR v2;INNOGENETICS N.V, Ghent, Belgium) were applied to determine target mutations of the viral polymerasegene in positive HBV-DNA samples. A total of 41 mutations located in 21 different codons were detected in thecurrent results. In 17 (41.5%) patients various point mutations were detected leading to lamivudin, adefovir and/or combined drug resistance. Wild polymerase gene profiles were detected in 24 (58.5%) HBV positive patients ofthe current cohort. Eight of the 17 samples (19.5%) having rtM204V/I/A missense transition and/or transversionpoint mutations and resistance to lamivudin. Six of the the mutated samples (14.6%) having rtL180M missensetransversion mutation and resistance to combined adefovir and lamivudin. Three of the mutated samples (7.5%)having rtG215H by the double base substituation and resistance to adefovir. Three of the mutated samples (7.5%)having codon rtL181W due to the missense transversion point mutations and showed resistance to combinedadefovir and lamivudin. Unreported novel point mutations were detected in the different codons of polymerasegene region in the current HBV positive cohort fromTurkish population. The current results provide evidencethat rtL180M and rtM204V/I/A mutations of HBV-DNA may be associated with a poor antiviral response andHBV chronicity during conventional therapy in Turkish patients.