Volume 7 Supplement 1

20th Brazilian Diabetes Society Congress

Open Access

Evaluation of high-risk type 1 diabetes HLA-DR and DQ haplotypes using three single nucleotide polymorphisms in a population from Southern Brazil

  • Guilherme Coutinho Kullmann Duarte1Email author,
  • Tais Silveira Assmann1,
  • Égina Marina Barbosa Martins1,
  • Mariana Lopes dos Santos1,
  • Luis Henrique Canani1 and
  • Daisy Crispim1
Diabetology & Metabolic Syndrome20157(Suppl 1):A215

https://doi.org/10.1186/1758-5996-7-S1-A215

Published: 11 November 2015

Background

Type 1 diabetes mellitus (T1D) accounts for ~10% of all diabetes cases, and it is caused by autoimmune destruction of pancreatic beta-cells, which leads to insulin deficiency and fates individuals to require insulin treatment to survive. The triggering of autoimmunity against beta-cells is caused by interaction between environmental and genetic risk factors. Among the several loci associated with T1D, the human leukocyte antigen (HLA) class II DR/DQ locus is the main genetic risk factor for T1D, accounting for 30-50% of genetic risk for this disease. Other genes have been associated with minor effects on T1D risk when compared with HLA, with different studies indicating that the effect of non-HLA polymorphisms on predisposition for T1D may be different according to HLA DR/DQ types. In this scenario, a recent study identified a minimum set of three polymorphisms (rs3104413, rs2854275, rs9273363) which can predict high-risk HLA-DR/DQ types relevant to T1D.

Objective

To evaluate frequencies of high-risk T1D HLA-DR/DQ haplotypes in a Southern Brazilian population using a minimum set of HLA polymorphisms (rs3104413C/G, rs2854275A/C and rs9273363A/C).

Materials and methods

We analyzed 387 T1D patients (cases) and 375 healthy blood-donor subjects (controls). The local ethics committee approved the protocol, and all patients signed an informed consent form. Polymorphisms of interest were genotyped by allelic discrimination – RT-PCR technique using TaqMan MGB probes (Life Technologies). Haplotype combinations of the three analyzed polymorphisms were used for defining the HLA types relevant to T1D (Nguyen et al*), distinguishing the highest-risk DR4-DQ8 and DR3/4-DQ types.

Results

Minor alleles frequencies of rs3104413, rs2854275, rs9273363 were increased in T1D patients as compared to non-diabetic subjects (rs3104413C: 44.4% vs. 11.2%; rs2854275A: 12.9% vs. 1.9%; rs9273363A: 43.9% vs. 9.9%; all P <0.0001).The frequency of high-risk DR4-DQ8 type was 66.7% in T1D cases and 15.3% in controls (OR=11.059, 95%CI 6.68-18.29; P <0.0001).The high-risk DR3/4-DQ8 heterozygous haplotype was observed in only one T1D patients and in none control subject.

Conclusion

As expected, the high-risk HLA-DR4/DQ8 haplotype is associated with increased risk for T1D in our population. The genetic risk of non-HLA genes on T1D in Southern Brazil can now be correct for different high-risk HLA-DR/DQ types.

Authors’ Affiliations

(1)
Hospital de Clínicas de Porto Alegre

References

  1. Nguyen , et al: Diabetes. 2013, 62: 2135-40.PubMedPubMed CentralView ArticleGoogle Scholar

Copyright

© Duarte et al. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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