Frequency of YMDD mutations in patients with chronic hepatitis B untreated with antiviral medicines

Investigators were suspicious of tyrosine-methionine-aspartate-aspartate (YMDD) mutations occurred only in patients who were treated by lamivudine. However, YMDD mutations of hepatitis B virus gene (HBV DNA) in patients with chronic hepatitis B (CHB) untreated with antiviral medicines was reported in some studies. The aim of this study was to evaluate YMDD mutations in Iranian Patients with chronic hepatitis B (CHB) untreated with antiviral medicines. In a cross sectional study, 151 adult patients with positive Hepatitis B surface antigen (HBsAg) (78 asymptomatic hepatitis B virus carriers, 73 active chronic hepatitis B patients or cirrhosis patients) were evaluated for YMDD mutants. The patients who were treated with interferon and Lamivudine or Adfovier in one year prior to the study were excluded. YMDD mutations of HBV DNA were detected by PCR-RFLP (PCR Restriction Fragment Length Polymorphism) in a single laboratory. The mean (±SD) age of patients was 37±4 years. Eighty one (54%) cases were male and 70 (46%) were female. Eight cases (5.3%) out of 151 had YMDD mutations. The type of mutation in all of these patients was YSDD. There was no significant relationship between YMDD mutation and viral load and HDV Ab (p>0.05). The mutant strains of the YMDD motif of HBV polymerase can be found in some patients without lamivudine treatment. However, in view of rather clinically insignificant YMDD mutation frequency, routine testing for YMDD mutations prior to antiviral therapy is not recommended in these patients.