title: DQB1*0202 and the new DQB1*0203 allele: a fourth pair of DQB1 alleles differing only at codon 57.
abstract: Amino acid 57 of DQ beta chains is of functional importance as it influences peptide binding, is part of B and T cell epitopes, and is associated with susceptibility and resistance to insulin-dependent diabetes mellitus and humoral immunodeficiencies. Polymorphism of codon 57 is conserved in primates and in HLA class II B genes implying that balancing selection operates on this residue. Previously, three DQB1 allele pairs have been described, that only differ at residue 57. In an African-American Black individual with the HLA phenotype A23.30;B58,63;Cw6;DR18,12;DR52;DQ5,2, we found a fourth example of this dimorphism: the new DQB1*0203 allele, that was identical to DQB1*0202 except for codon 57, which encodes aspartic acid and alanine respectively in the two alleles. The class II haplotype carrying the new allele was deduced to be DRB1*0302,DRB3*0101,DQA1*05011,DQB1*0203.
authors.affiliation: Department of Bioscience, Novum, Karolinska Institute, Huddinge, Sweden.
authors.forename: O
authors.initials: O
authors.lastname: Olerup
authors.forename: A
authors.initials: A
authors.lastname: Aldener-Cannavá
authors.forename: A
authors.initials: A
authors.lastname: Fogdell-Hahn
authors.forename: R R
authors.initials: RR
authors.lastname: Getty
authors.forename: D R
authors.initials: DR
authors.lastname: Wagenknecht
authors.forename: J A
authors.initials: JA
authors.lastname: McIntyre
mesh_terms: D000483:Alleles; D001483:Base Sequence; D003062:Codon; D018076:DNA, Complementary; D005091:Exons; D006683:HLA-DQ Antigens / Q000145:classification / Q000235:genetics*; D059866:HLA-DQ beta-Chains; D006801:Humans; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid
chemical_list: D003062:Codon; D018076:DNA, Complementary; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen