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Disease Markers
Volume 21, Issue 3, Pages 139-145

Estimation of Diabetes Risk in Brazilian Population by Typing for Polymorphisms in HLA-DR-DQ, INS and CTLA-4 Genes

Omar M. Hauache,1,2 André F. Reis,1,2 Carolina S.V. Oliveira,1 José Gilberto H. Vieira,1,2 Minna Sjüroos,3 and Jorma Ilonen4

1Escola Paulista de Medicina/UNIFESP, Sao Paulo, SP, Brazil
2Fleury Institute, Sao Paulo, SP, Brazil
3PerkinElmer Life and Analytical Sciences, Turku, Finland
4JDRF Centre for Prevention of Type 1 Diabetes in Finland and Department of Virology, University of Turku, Turku, Finland

Received 21 October 2005; Accepted 21 October 2005

Copyright © 2005 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The study aimed to further characterise HLA encoded risk factors of type 1 diabetes (T1D) in Brazilian population and test the capability of a low resolution full-house DR-DQ typing method to find subjects at diabetes risk. Insulin and CTLA-4 gene polymorphisms were also analysed. The method is based on an initial DQB1 typing supplemented by DQA1 and DR4 subtyping when informative. Increased frequencies of both (DR3)-DQA1*05-DQB1*02 and DRB1*04-DQA1*03-DQB1*0302 haplotypes were detected among patients. DRB1*0401, *0402, *0404 and *0405 alleles were all common in DQB1*0302 haplotypes and associated with T1D. (DRB1*11/12/1303)-DQA1*05-DQB1*0301, (DRB1*01/10)-DQB1*0501, (DRB1*15)-DQB1*0602 and (DRB1*1301)-*0603 haplotypes were significantly decreased among patients. Genotypes with two risk haplotypes or a combination of a susceptibility associated and a neutral haplotype were found in 78 of 126 (61.9%) T1D patients compared to 8 of 75 (10.7%) control subjects (P < 0.0001). Insulin gene −2221 C/T polymorphism was also associated with diabetes risk: CC genotype was found among 83.1% of patients compared to 69.3% of healthy controls (P = 0.0369, OR 1.98) but CTLA-4 gene +49 A/G polymorphism did not significantly differ between patients and controls. Despite the diversity of the Brazilian population the screening sensitivity and specificity of the used method for T1D risk was similar to that obtained in Europe.