[Mutation of hepatitis B virus S gene in children with hepatitis B virus-associated glomerulonephritis].
OBJECTIVE
Hepatitis B virus-associated glomerulonephritis (HBV-GN) is an immune complex-mediated glomerulonephritis. The present study was conducted to identify HBV S gene mutation in children with HBV-GN.


METHODS
Serum HBV DNA was extracted in 53 children, including 30 with HBV-GN, 5 with HBV-carrying nephrosis (control group 1), and 18 HBV carriers (control group 2). HBV S gene sequence was amplified by polymerase chain reaction (PCR). The PCR products were sequenced directly and compared with AY167097.1, an epidemic HBV strain in China.


RESULTS
(1) The adw serotype of HBV was found in all the 30 cases with HBV-GN, 5 cases with HBV-carrying nephrosis and 17 HBV carriers except for 1, in whom adr serotype was identified. (2) HBV genotype B was found in 29 children with HBV-GN, 5 cases with HBV-carrying nephrosis and 17 HBV carriers, genotype E was found in a child with HBV-GN, and genotype C in an HBV carrier. (3) A total of 17 kinds of different single nucleotide change in HBV S gene were identified in 21 of 30 (70%) HBV-GN patients. Among them, 16 of 21 (76.2%) nucleotide mutations resulted in amino acid substitution. It was interesting that most (11/16, 68.8%) amino acid substitutions involved threonine, serine and tyrosine, the potential phosphorylation sites of mitogen-activated protein kinase (MAPK) and protein tyrosine kinase (PTK) in HBV protein. Single nucleotide changes which didn not result in amino acid substitution were found in 2 HBV-carrying nephrosis patients, 2 HBV carriers and 5 cases with HBV-GN.


CONCLUSIONS
Single nucleotide changes in HBV S gene were found in most children with HBV-GN. Most mutations in HBsAg resulted in amino acid substitutions involving threonine, serine and tyrosine, which may play a role in the pathogenesis of HBV-GN.
Zhu
Hui
H
Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Lu
Hong-zhu
HZ
Zhou
Jian-hua
JH
Wu
Heng-sheng
HS
Fang
Feng
F
D019943:Amino Acid Substitution; D002353:Carrier State; D002648:Child; D004252:DNA Mutational Analysis; D004279:DNA, Viral / Q000235:genetics; D005796:Genes; D005838:Genotype; D005921:Glomerulonephritis / Q000821:virology*; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D009154:Mutation; D014759:Viral Envelope Proteins / Q000235:genetics*
D004279:DNA, Viral; C118669:S envelope protein, hepatitis B virus; D014759:Viral Envelope Proteins