Heward, J. M.; Mijovic, C. H.; Kelly, M. A.; Morrison, Errol Y.; Barnett, A. H.
Author Affiliation, Ana.
Department of Basic Medical Sciences
HLA-DQ and DRB1 polymorphism and susceptibility to type 1 diabetes in Jamaica
European Journal of Immunogenetics
Date of Publication
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-DQ8and 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 1506-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.....