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Different Alleles Cause an Imbalance in A 2 and A 2 B Phenotypes of the ABO Blood Group
Author(s) -
Ogasawara Kenichi,
Yabe Ryuichi,
Uchikawa Makoto,
Bannai Makoto,
Nakata Kenichi,
Takenaka Michiko,
Takahashi Yuji,
Juji Takeo,
Tokunaga Katsushi
Publication year - 1998
Publication title -
vox sanguinis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.68
H-Index - 83
eISSN - 1423-0410
pISSN - 0042-9007
DOI - 10.1046/j.1423-0410.1998.7440242.x
Subject(s) - abo blood group system , phenotype , allele , genetics , biology , genotype , allele frequency , polymorphism (computer science) , heterozygote advantage , polymerase chain reaction , gene
Background and Objectives : In several populations, including the Japanese, the frequency of the A 2 B phenotype is significantly higher than expected based on the A 2 phenotype frequency. To understand the genetic basis of this ‘excess’ of A 2 B, we examined ABO alleles in individuals with A 2 ‐related phenotypes. Materials and Methods : ABO alleles were identified by means of polymerase chain reaction single‐strand conformation polymorphism (SSCP) and nucleotide sequence analyses. Results : The frequencies of A 2 ‐related alleles (* A105 , * A106 , * A107 , * A111 and * R101 ) were clearly different between the A 2 and A 2 B phenotypes. In particular, a putative recombinant allele, * R101 , was uncommon in the A 2 but common in the A 2 B phenotype individuals. This allele was also detected in 4 of 401 (1%) unrelated A 1 phenotype (AO genotype) individuals. Conclusion : * R101 is presumably expressed as phenotype A 1 in * R101 /* O heterozygous individuals, but as phenotype A 2 in * R101 /* B heterozygotes, thus giving rise to a high A 2 B phenotype frequency.