title: [Analysis on mutation of S gene and P gene of hepatitis B virus in two counties of Sichuan Province].
abstract: OBJECTIVE
  To analyze HBV S gene/P gene mutation in 2 counties (districts) of Sichuan province.
  
  
  METHODS
  HBV DNA were extracted from sera positive both for HBsAg and HBeAg. After PCR and nucleotide sequencing, nucleotide/amino acid mutation in S and P gene were compared and analyzed.
  
  
  RESULTS
  Of 47 serum samples from patients with chronic HBV infection, amino acid mutation in 'a' determinant occurred in 12 samples (25.53%,12/47), correlating with T126A, I126T/S, P127T, T131N, M133L, M133T and T140I; high proportion of mutation clustered in first loop of 'a' determinant (92.86%,13/14), rtV207I mutation in C domain of reverse transcription occured in one sample.
  
  
  CONCLUSIONS
  Naturally occurring mutation in 'a' determinant clustered predominantly in the first loop and usually associated with altered antigenicity, posing a potential threat to successfully vaccinated individuals; Lamivudine-resistant mutant might occur in patient even without nucleotide analogue treatment.
authors.affiliation: Sichuan Provincial Center for Disease Control and Prevention, Chengdu 610041, Sichuan, China.
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Tong
authors.forename: Ji-Lan
authors.initials: JL
authors.lastname: He
authors.forename: Li
authors.initials: L
authors.lastname: Sun
mesh_terms: D000595:Amino Acid Sequence; D002681:China; D015684:Gene Products, pol / Q000737:chemistry / Q000235:genetics*; D006509:Hepatitis B / Q000821:virology*; D006514:Hepatitis B Surface Antigens / Q000737:chemistry / Q000235:genetics*; D006515:Hepatitis B virus / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D016415:Sequence Alignment
chemical_list: D015684:Gene Products, pol; D006514:Hepatitis B Surface Antigens; C066027:P protein, Hepatitis B virus