Objective: To find different mutated status of HBV DNA in circulation from chronic HBV patients.
Methods: Specially designed primers and polymerase chain reaction method were applied to amplify the whole S gene of HBV from the serum of 2 patients. After being sequenced, 4 clones were compared with HBV adr subtype (China strain) to identify the mutant sites.
Results: Sequencing results implied that there was a truncated large/middle S gene in the serum of the patients. Besides that, HBsAg and HBV DNA polymerase defective clones were also detected.
Conclusions: Truncated middle S gene is found in the circulation of patients with chronical HBV infection, suggestive of a poor prognosis.