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 flare- up. this data suggests that monitoring of adv-resistance mutations in adv naïve patients can be considered in selecting the appropriate anti-viral regimen.