Study on Hepatitis B Virus Pre-S/S Gene Mutations in Children with Chronic Hepatitis B Infection

ABSTRACT

PURPOSE: Hepatitis B virus(HBV) with various mutations has been reported. The aims of this study were to investigate the frequency and manifestation of HBV pre-S/S mutations in children with chronic hepatitis B infection. METHODS: Sera from 17 children with chronic hepatitis B infection were analyzed by direct sequencing of polymerase chain reaction amplification of HBV DNA. Results: Seventeen cases of adr type were analyzed. The deletions in HBV pre-S region were observed in 3(17.6%) of 17 cases. Of 3 deleted cases, 2 had an in-phase deletion in the pre-S1 region spanning 18 bp. Another case had a 18 bp and 3 bp deletions in the pre-S1 region. Many point mutations in HBV pre-S region were detected in all cases and these mutations were observed more frequently in the pre-S2 region than the pre-S1 region. Six point mutations in the pre-S1 region were observed. Eight point mutations in pre-S2 region were observed. Point mutations in the S region were detected in 14(82.4%) of 17 cases. Among these, mutations of the "a" determinant were detected in 4(23.5%) of 17 cases. Mutations at codon 130 and at codon 146 were noted in 2 cases. Combined mutations at codon 124, 126, 146 and at 130, 131, 136, 146 were noted in the other 2 cases. Mutations except "a" determinant region included at codon 3, 29, 73, 120, 184, 214, 226, 227. CONCLUSION: These observations suggest that deletion and point mutations in HBV pre-S1, pre- S2 regions and point mutations in HBV S region are frequent in the children with chronic hepatitis B infection.