A PCR-RFLP based protocol for the detection of hepatitis B virus variants in some lamivudine-untreated chronic hepatitis B virus carriers in Pakistan

Hepatitis B virus (HBV) affects more than 350 million people worldwide and is a leading cause of morbidity and mortality in developing countries like Pakistan. Lamivudine has potential to inhibit hepatitis B virus (HBV) replication but long term lamivudine treatment results in mutations in YMDD region of HBV, making this therapy ineffective. In this study, we have optimized a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based protocol to detect two mutations in HBV DNA polymerase gene (at codon 528 and 552) in chronic hepatitis patients, without any prior lamivudine treatment. HBV genome was extracted and tested by PCR-RFLP for detection of mutations in polymerase gene. Variations in HBV genome were not detected in enrolled patients confirming that lamivudine can be used to treat chronic Hepatitis B in these patients. Several studies have reported the natural occurrence of mutation in YMDD motif of polymerase gene in chronic hepatitis B patients, not treated with lamivudine, but these mutants were not detected in Pakistani lamivudine-untreated chronic hepatitis B patients.