title: A unique 502C>T mutation in exon 7 of ABO gene associated with the Bel phenotype in Taiwan.
abstract: BACKGROUND
  The ABO system includes many variant subgroups. Some of them are difficult to identify serologically, leading to mistyping of blood groups. For example, Bel is often typed as O blood group.
  
  
  METHODS
  DNA sequencing and a molecular approach were explored to accurately determine the genotypes of Bel subgroups. Seven Bel blood donors and 106 individuals with other blood groups were analyzed serologically and molecularly.
  
  
  RESULTS
  The serologic results of these seven Bel blood donors showed that their RBCs do not react with anti-B or anti-A,B, and their B antigen was detected by adsorption and elution methods. Sequencing results for exons 6 and 7 of ABO genes showed a new Bel allele with a C>T substitution at nucleotide position 502 in exon 7 of the ABO gene in all seven cases but not in other blood groups. Consequently, an amplification-created restriction site protocol was designed to detect the 502C>T genotype in Bel subgroup cases.
  
  
  CONCLUSIONS
  A novel 502C>T mutation was found in the Bel subgroup in Taiwan and successfully developed a rapid and accurate molecular protocol to detect this mutation. To our knowledge, the new Bel allele that was found is unique in Taiwanese residents.
authors.affiliation: Taipei Blood Center, Chinese Blood Service Foundations, Taipei, Taiwan.
authors.forename: P-H
authors.initials: PH
authors.lastname: Lin
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.forename: S-J
authors.initials: SJ
authors.lastname: Lin-Tsai
authors.forename: K-T
authors.initials: KT
authors.lastname: Lin
authors.forename: J-M
authors.initials: JM
authors.lastname: Chen
authors.forename: D-C
authors.initials: DC
authors.lastname: Chu
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics*; D000483:Alleles; D001782:Blood Donors; D004252:DNA Mutational Analysis / Q000379:methods*; D005091:Exons; D005838:Genotype; D006801:Humans; D010641:Phenotype; D017354:Point Mutation; D013624:Taiwan
chemical_list: D000017:ABO Blood-Group System