Study on the YMDD mutation during lamivudine therapy in hepatitis B patients with different HBV genotypes

Objective To study the tyrosine-methionine-aspartate-aspartate(YMDD) mutation during lamivudine therapy in hepatitis B patients with different Hepatitis B virus(HBV) genotypes.Methods Real-time fluorescence polymerase chain reaction(PCR) and gene sequencing were used for the detection of HBV DNA levels,YMDD mutants and HBV genotypes in serum samples of 115 hepatitis B patients during lamivudine therapy.Results The HBV DNA positive rates in patients with lamivudine therapy time less than 12 months,12 to 24 months and more than 24 months were 75%,35% and 16%,and YMDD mutation rates were 22%,54% and 100%,respectively.Among 115 hepatitis B patients in Dalian,the proportions of genotype B,C and B-C mixed-type were 17%,75% and 8%,respectively.The YMDD mutation rates of genotype B and C were 21% and 19.5%.There was no YMDD mutation in patients with B-C mixed-type.It showed no significant correlation between HBV DNA genotypes and YMDD mutation rates(P0.05).Conclusions During lamivudine therapy,there is no relation between the YMDD mutation and the HBV genotypes.