Interleukin 6 −174(G>C) gene polymorphism is related to celiac disease and autoimmune thyroiditis coincidence in diabetes type 1 children

The aim of the study was to assess the relationship between IL-6 gene polymorphism at −174(G>C) and the coincidence of celiac and autoimmune thyroid diseases with type 1 diabetes mellitus (DM1) in children. 200 children with DM1 aged 13.23 ± 3.54 years and 172 healthy controls were analyzed. The IL-6 gene −174(G>C) polymorphism at the promoter region of the gene was analyzed by the PCR-RFLP method. The genotype distribution was significantly different in diabetic children as compared to the healthy controls (p = 0.01). In DM1 patients GC heterozygotes were the most common (52.5%), while CC homozygotes accuted for 29% and GG homozygotes only for 18% of cases. In contrast, GG homozygotes were much more frequent among healthy children (31%). Besides, the GG homozygotes were significantly more frequent among diabetic children with celiac disease (p = 0.04) in relation to those without autoimmune complications. In children with autoimmune thyroiditis, the distribution of the IL-6 genotypes was similar to that seen in diabetic patients without autoimmune complications (p = 0.24). The results of our study suggest that the diabetic children, who have IL-6 gene −174GG genotype may have an increased risk for celiac disease development.