Premium
Association of IL‐18 promoter polymorphisms with predisposition to Type 1 diabetes
Author(s) -
Mojtahedi Z.,
Naeimi S.,
Farjadian S.,
Omrani G. R.,
Ghaderi A.
Publication year - 2006
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.2006.01786.x
Subject(s) - medicine , genotype , type 2 diabetes , single nucleotide polymorphism , allele , diabetes mellitus , polymorphism (computer science) , case control study , allele frequency , genetic predisposition , genotype frequency , genetics , immunology , gene , endocrinology , biology , disease
Aims IL‐18, a potent IFN‐γ‐inducing cytokine, is capable of polarizing the immune response to a Th1 phenotype. Recent studies have demonstrated an association between single‐nucleotide polymorphisms located at positions −607 (A/C) and −137 (C/G) in the promoter region of IL‐18 gene and Type 1 diabetes. The aim of the present study was to determine whether the same polymorphisms of the gene were associated with Type 1 diabetes in Iranians. Methods In 112 patients with Type 1 diabetes and 194 non‐diabetic control subjects, these two single‐nucleotide polymorphisms were analysed by sequence‐specific PCR. Results Allele and genotype frequencies of the IL‐18 gene polymorphisms were similar in the whole group of Type 1 diabetic patients and controls. However, categorizing patients according to age at onset of diabetes revealed a significant difference in distribution of the genotypes at position −137 between patients with older age at onset (> 15 years) (GG 49%, GC 34%, CC 17%) and control subjects (GG 57.7%, GC 36.6%, CC 5.7%) ( P = 0.027). Frequency of the C allele at position −137 was significantly higher in these patients than in controls ( P = 0.038). Moreover, there was an association between −607AA/−137CC genotype combination and susceptibility to Type 1 diabetes in this subgroup of patients ( p c = 0.027). Conclusions The results of this study show that polymorphisms of IL‐18 promoter confer susceptibility to Type 1 diabetes in Iranian individuals with onset at older ages. Further investigations are necessary to clarify the effect of IL‐18 variants on immune regulation.