Detection of rtN236T mutation associated with adefovir dipivoxil resistance in Hepatitis B infected patients with YMDD mutations in Tehran

Background objectives: the risk of adefovir dipivoxil resistance emergence has increased in lamivudine-resistant hepatitis b infected patients. the mutations known as causing adefovir resistance,rtn236t and rta181v/t,are detected within the d and b functional domain of the hbv polymerase,respectively. in this study,we intended to determine the pre-existing adefovir-resistance mutations in patients infected with lam resistant mutants prior to starting adefovir therapy. material and methods: the study included 30 patients with chronic hepatitis b with lamivudine resistance mutations in the ymdd motif that experienced viral breakthrough. results: after alignment of protein coding sequences,the rtn236t mutation was observed in two (6.6 %) patients,while twenty-eight others had neither rtn236t,nor rta181v/t mutation. all 30 patients were infected with genotype d of hepatitis b virus. conclusions: the early detection of lam-resistance mutations may allow a timely chance of therapy to avoid hepatitis flareup. this data suggests that monitoring of adv-resistance mutations in adv naïve patients can be considered in selecting the appropriate anti-viral regimen.