title: Molecular heterogeneity of the A3 subgroup.
abstract: The molecular characterization of the subgroup A3 remains unclear. Four unrelated A3 blood donors were studied. Family studies were possible in three of them. The A3 subgroup was defined by immunohaematological evaluation with four different commercially available serums. Exons VI and VII of the ABO gene, responsible for 91% of the catalytic active part of the glycosyltransferase, were amplified and subjected to direct sequencing. The results in all samples showed heterozygosity for the G261 deletion. In the A3 allele, the following associations were found: C467T mutation and 1060C deletion in one A3 blood donor and in another G829A and 1060C. In one case, only the 1060C deletion was demonstrated in the A3 allele. One blood donor presented the T646A and the G829A mutations in homozygosity. It was concluded that the A3 blood group is very heterogeneous at the molecular level.
authors.affiliation: Haemocentro/Department of Internal Medicine University of Campinas, Campinas, SP-Brazil. maluz@unicamp.br
authors.forename: M L
authors.initials: ML
authors.lastname: Barjas-Castro
authors.forename: M H
authors.initials: MH
authors.lastname: Carvalho
authors.forename: M F
authors.initials: MF
authors.lastname: Locatelli
authors.forename: S
authors.initials: S
authors.lastname: Bordin
authors.forename: S T
authors.initials: ST
authors.lastname: Saad
mesh_terms: D000017:ABO Blood-Group System / Q000145:classification / Q000235:genetics* / Q000276:immunology; D001788:Blood Grouping and Crossmatching; D004252:DNA Mutational Analysis; D004912:Erythrocytes / Q000276:immunology; D005091:Exons; D005192:Family Health; D005260:Female; D016368:Frameshift Mutation; D014644:Genetic Variation / Q000276:immunology; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D010375:Pedigree; D010641:Phenotype; D017354:Point Mutation; D012699:Serology
chemical_list: D000017:ABO Blood-Group System