fa جهش های مقاومت به لامیوویدین در بیماران هپاتیت B مزمن تحقيقي Original Paper Abstract Background and Objective: Lamivudine is the first orally available drug approved for treatment of chronic hepatitis B. Mutations at the YMDD and FLLAQ motifs in the domains of HBV polymerase gene contribute resistance to lamivudine. This study was aimed to determine the rate of YMDD and FLLAQ mutants in hepatitis B patients in Golestan Province, Iran. Material and methods: In this cross sectional study, 120 patients with chronic HBV infection were recruited. Of them, 55 were treated and 65 untreated with Lamivudine. HBV DNA extractions from plasma and polymerase chain reaction (PCR) were performed. For detection of Lamivudine mutants direct sequencing and alignment of products were applied using reference sequence from Gene Bank database. Results: the average age of patients was 36.31±10.07, which 35% of them were female and 65% were male. Mutations at the YMDD and FLLAQ motifs in the domains of HBV polymerase gene were detected in 12 of 55 patients (21.81%) treated with Lamivudine while no mutation was observed in in untreated patients. The YMDD and FLLAQ mutants were detected in 9.16% (11/120) and 0.83% (1/120) of chronic HBV patients, respectively. Conclusion: Usual HBV mutations, which play an important role in lamivudine resistance, detected in this study are similar to other studies. Key words: Hepatitis B Viruse, YMDD Mutation, Lamivudine, Iran. Hepatitis B Viruse, YMDD Mutation, Lamivudine, Iran. 7 13 http://mlj.goums.ac.ir/browse.php?a_code=A-10-1-263&slc_lang=fa&sid=1 Rezanezhadi, M معصومه رضانژادی 100319475328460012640 100319475328460012640 No Islamic Azad University, Damghan Branch, Iran دانشگاه آزاد اسلامی واحد دامغان Tabarraei, A علیجان تبرائی aligant@yahoo.com 100319475328460012641 100319475328460012641 Yes Infectious Diseases Research Centre, Golestan University of Medical Sciences, Gorgan, Iran دانشگاه علوم پزشکی گلستان Zhand, S ساره ژند 100319475328460012642 100319475328460012642 No Golestan University of Medical Sciences, Gorgan, Iran دانشگاه علوم پزشکی گلستان Moradi, A عبدالوهاب مرادی 100319475328460012643 100319475328460012643 No Golestan University of Medical Sciences, Gorgan, Iran دانشگاه علوم پزشکی گلستان Nezamzade, R رضا نظام زاده 100319475328460012644 100319475328460012644 No Islamic Azad University, Damghan Branch, Iran دانشگاه آزاد اسلامی واحد دامغان Vakili, MA محمد علی وکیلی 100319475328460012645 100319475328460012645 No Infectious Diseases Research Centre, Golestan University of Medical Sciences, Gorgan, Iran دانشگاه علوم پزشکی گلستان