title: HLA-DQ and DRB1 polymorphism and susceptibility to type 1 diabetes in Jamaica.
abstract: Genetic susceptibility to type 1 diabetes is determined by a combination of HLA-DQ and DRB1 alleles. In the present study, HLA associations with type 1 diabetes were investigated in the Jamaican population. DRB1 and DQ genotyping was performed on 45 type 1 diabetic patients and 132 control subjects born and resident in Jamaica. The small number of patients available for study reflected the low prevalence of type 1 diabetes in Jamaica. The results were compared with those from other African heritage populations and white Caucasians. The highest relative risk was associated with the DRB1*03-DQ2/DRB1*04-DQ8 genotype. Both DRB1*0401-DQ8 and DRB1*0408-DQ8 were positively associated with disease. DRB1*0408-DQ8 is uncommon amongst white Caucasians, where DRB1*0401-DQ8 is the major predisposing haplotype. The DRB1*1503-DQ6 haplotype was associated with protection from diabetes in the Jamaican population. This haplotype is rare amongst white Caucasians, where DRB1*1501-DQ6 is the protective haplotype. Data from African heritage populations suggest that DRB1*1503-DQ6 might be less protective than DRB1*1501-DQ6. DRB1*03-DQA1*0401-DQB1*0402 was associated with protection from diabetes in the Jamaican population, whereas in white Caucasians DRB1*08-DQA1*0401-DQB1*0402 is predisposing. These data demonstrate that comparison of genetic associations with type 1 diabetes in races with population-specific DRB1-DQ haplotypes provides new information as to the exact determinants of disease susceptibility. Further support is provided for roles of the DQ genes and the DRB1 gene (or a gene in linkage disequilibrium with it) in determining susceptibility to type 1 diabetes.
authors.affiliation: Department of Medicine, Division of Medical Sciences, University of Birmingham, Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK. j.m.heward@bham.ac.uk
authors.forename: J M
authors.initials: JM
authors.lastname: Heward
authors.forename: C H
authors.initials: CH
authors.lastname: Mijovic
authors.forename: M A
authors.initials: MA
authors.lastname: Kelly
authors.forename: E
authors.initials: E
authors.lastname: Morrison
authors.forename: A H
authors.initials: AH
authors.lastname: Barnett
mesh_terms: D000328:Adult; D044383:Black People / Q000235:genetics; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology; D020022:Genetic Predisposition to Disease; D006683:HLA-DQ Antigens / Q000235:genetics*; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006239:Haplotypes; D006801:Humans; D007563:Jamaica; D011110:Polymorphism, Genetic; D044465:White People / Q000235:genetics
chemical_list: D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; C553505:HLA-DRB1*04:01 antigen