title: [Study on a novel mutation of B glycosyltransferase gene related with an ABx variant].
abstract: OBJECTIVE
  To explore the molecular basis of an individual featuring an ABx variant of ABO blood group system.
  
  
  METHODS
  Serological assays were used to characterize the erythrocyte phenotypes and salivary ABH secretors. All of the seven exons and flanking introns of ABO glycosyltransferase gene were amplified with polymerase chain reaction (PCR). And the products were sequenced bidirectionally following enzyme digestion. Exons 6 and 7 were also subcloned and analyzed for haplotypes of the ABO gene.
  
  
  RESULTS
  Erythrocytes of the proband have expressed a strong A antigen and a weak B antigen, which was identified as a rare ABx variant in addition with other serological features. Nine heterozygous sites in exon 6 (297A/G) and exon 7 (467C/T, 526C/G, 657C/T, 703G/A, 796C/A, 803G/C, 808T/A, 930G/A) of the coding region of the ABO gene were identified. Based on haplotype analysis, one allele was determined as common A102, whilst another was consistent with B101 except for an 808T>A mutation which has resulted in replacement of phenylalanine with isoleucine at position 270 of glycosyltransferase B.
  
  
  CONCLUSIONS
  The 808T>A mutation of the glycosyltransferase B gene may decrease the enzymatic activity and result in the Bx variant.
authors.affiliation: Central Blood Station, Yiwu, Zhejiang, People's Republic of China.
authors.forename: Wen-jian
authors.initials: WJ
authors.lastname: Hu
authors.forename: Guang-cheng
authors.initials: GC
authors.lastname: Fu
authors.forename: Xian-guo
authors.initials: XG
authors.lastname: Xu
authors.forename: Fa-ming
authors.initials: FM
authors.lastname: Zhu
authors.forename: Hang-jun
authors.initials: HJ
authors.lastname: Lv
authors.forename: Li-xing
authors.initials: LX
authors.lastname: Yan
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics*; D000328:Adult; D005091:Exons; D005260:Female; D016695:Glycosyltransferases / Q000235:genetics*; D006239:Haplotypes; D006801:Humans; D009154:Mutation
chemical_list: D000017:ABO Blood-Group System; D016695:Glycosyltransferases