Complete hepatitis B virus genome analysis in chronically infected children before and during lamivudine treatment

Spontaneous HBV YMDD motif mutations in patients with familially clustered chronic HBV infection

AIM: To survey the spontaneous hepatitis B virus (HBV) YMDD mutations in patients with familially clustered chronic HBV infection.

METHODS: Ninety-five chronic hepatitis B (CHB) patients, who came from 34 CHB cluster families and did not underwent treatment with any antiviral drugs, and 82 sporadic CHB patients, who did not underwent treatment with any antiviral drugs, were included in this study. YMDD mutations were detected and compared between the two groups of patients.

RESULTS: Of the 95 patients with familial clustering of chronic HBV infection, spontaneous YMDD variants were detected in 51 patients (53.68%). Of the 82 sporadic CHB patients, YMDD variants were detected in 21 patients (25.61%). The detection rate of spontaneous YMDD mutations was significantly higher in CHB patients with familial clustering than in sporadic CHB patients (P < 0.05).

CONCLUSION: The detection rate of spontaneous YMDD mutations is higher in CHB patients with familial clustering than in those without familial clustering.

Advances in research on natural YMDD mutations in the hepatitis B virus DNA polymerase in patients with chronic hepatitis B

Mutations of the hepatitis B virus (HBV) DNA polymerase, mainly occurring in the YMDD region, are related to resistance to lamivudine. Although these mutations often occur after lamivudine use, they can also emerge naturally. Many scholars have demonstrated the existence of natural YMDD mutations. Although many methods are currently used to detect YMDD mutations, a unified approach for detection of YMDD mutations is still unavailable. The emergence of YMDD mutations may be associated with HBV DNA levels and genotypes.

Hepatitis B virus genotype G epidemiology and co-infection with genotype A in Canada

Hepatitis B virus (HBV) genotype G (HBV/G) is an unusual variant, and little is known about its epidemiology and natural history, particularly the requirement for a co-infecting HBV genotype and their relationship during infection. This study investigated the quasispecies nature of co-infecting genotypes in 39 samples collected over a 6 year period from 13 HBV/G-infected patients. HBV/G infections were found to occur predominantly in males (92 %) and were primarily associated with male homosexual sex (67 %). All patients were infected with HBV/G and HBV/A, or a recombinant HBV/A/G strain. Co-infecting genotypic prevalence was often observed to fluctuate over time, with periods of HBV/G monoinfection in some patients. The average sequence divergence among Canadian HBV/G strains was 1.57+/-0.62 %. Thus, all HBV/G infections in Canada occur in the context of co-infection or recombination with HBV/A, and strains display increased sequence divergence compared with all known HBV/G sequences described to date.