Sequencing of the second exon of the MHC class II DQ6 alleles in patients with type 1 diabetes.
The MHC class II molecule DQ6 is strongly associated with protection from type 1 diabetes. A small number of diabetic subjects have been typed as positive for DQ6, but it has been suggested that these individuals may possess a mutant form of the molecule, which is structurally altered in such a way as to abrogate its protective effect. In order to test this hypothesis, eight diabetic individuals positive for DQ6 were investigated. The second exons of the alleles encoding DQ6, DQA1*0102 and DQB1*0602, were sequenced using fluorescently labelled dideoxynucleotides. No mutations were found. This suggests that all the subjects possessed the "wild-type" second exons of the DQ6 alleles and, hence, that the protective effect associated with the antigen-binding domain of DQ6 is not absolute.
Rayner
M L
ML
Department of Medicine, Queen Elizabeth Hospital, Edgbaston, Birmingham, UK. m.l.rayner@bham.ac.uk
Kelly
M A
MA
Mijovic
C H
CH
Barnett
A H
AH
D000293:Adolescent; D000328:Adult; D000483:Alleles; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics*; D005091:Exons / Q000235:genetics*; D006683:HLA-DQ Antigens / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D017422:Sequence Analysis, DNA
D006683:HLA-DQ Antigens; C063831:HLA-DQ6 antigen