Evaluation of histo-blood group ABO genotyping in a Danish population: frequency of a novel O allele defined as O2.
Traditional blood group ABO serology is based on immunoreactivity with the carbohydrate determinants A, B and H antigens. Recent advances at the DNA level of the ABO genes have provided a molecular genetic model for the ABO polymorphism. This genetic model has to date only been tested on a limited basis. The present study was initiated to evaluate the universality of the proposed genetic model on a larger group of serologically defined ABO phenotypes. Three hundred healthy Danish blood donors were analysed (A:50, B:50, AB:50, O:150) by PCR amplification followed by diagnostic restriction enzyme cutting. In all cases A, B, and AB at least one allele of correctly predicted status was found. However, in O phenotype individuals, 11 out of 150 carried one allele discordant to the proposed genetic model. This novel O allele (3.7% allele frequency) was further characterized by diagnostic restriction enzyme analysis in two positions divergent between A and B alleles and by DNA sequencing of the two major exons. The novel O allele is termed O2 as it typed as B in nucleotide position 526 and as A in positions 703, 796, and 803, in contrast to the most predominant O allele termed O1, which types as A in all 4 positions. The structural defect in the O2 allele appears to be an additional substitution at nucleotide position 802. The results clearly demonstrate that with the addition of the two distinctly different O alleles, O1, O2, the previously proposed molecular genetic basis of the ABO polymorphism is quite valid.(ABSTRACT TRUNCATED AT 250 WORDS)
Grunnet
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Regional Center for Blood Transfusion and Clinical Immunology, Aalborg Hospital, Denmark.
Steffensen
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R
Bennett
E P
EP
Clausen
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H
D000017:ABO Blood-Group System / Q000235:genetics*; D000483:Alleles; D001483:Base Sequence; D003718:Denmark; D005069:Evaluation Studies as Topic; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008969:Molecular Sequence Data
D000017:ABO Blood-Group System