Interleukin 18 (IL18) gene promoter polymorphisms are associated with type 1 diabetes mellitus in Brazilian patients

- The SNP −137C/G at IL18 promoter was significantly associated with T1D onset.
- The SNPs −656 C/A and −607 G/T at IL18 promoter were not associated with T1D onset.
- No correlation was found with the IL18 promoter SNPs and the age onset of T1D.
- The IL18 promoter SNPs were not associated with the insurgence of AITD and CD.
- All SNPs in the studied groups were according to Hardy-Weinberg equilibrium.

Interleukin 18 (IL-18) is a cytokine that plays an important role in the Th1 response, by its ability to induce IFN-γ production in T cells and natural killer cells. Functional variants of IL18 gene has been reported as associated with type 1 diabetes (T1D). In the present study were analyzed three promoter single nucleotide polymorphisms (SNPs), at −656 (rs1946519), −607 (rs1946518) and −137 (rs187238) position, in 181 children and adolescents with T1D and 122 healthy individuals, both from metropolitan area of Recife, Northeast of Brazil. T1D patients were stratified according to the presence autoimmune thyroiditis and celiac disease. Allele and genotype frequencies of IL18 SNPs were Hardy-Weinberg equilibrium in patients and controls. The allele −137G and the haplotype −656G/−607C/−137G were more frequent in T1D patients (OR = 1.82 and 1.97, respectively) then in healthy controls. However, those SNPs were not associated with the age of T1D onset as well as with the insurgence of AITD and/or CD in concomitant with T1D patients. Our findings suggest an association between IL18 promoter SNPs and susceptibility to T1D in Brazilian patients.