Clinical signs of type 1 diabetes are associated with type 2 diabetes marker transcription factor 7‐like 2 polymorphism

AIMS/INTRODUCTION: We aimed to assess the distribution of transcription factor 7‐like 2 gene TCF7L2 (rs7903146) polymorphism and to find possible associations between TCF7L2 and the characteristics of type 1 diabetes. MATERIALS AND METHODS: We studied 190 newly diagnosed type 1 diabetes patients (median age 12.7 years, range 2.0–72.5) and 246 controls (median age 23.8 years, range 1.4–81.5) for TCF7L2 single nucleotide polymorphism. We determined anti‐islet autoantibodies, random C‐peptide levels, diabetes associated HLA DR/DQ haplotypes and genotypes in all patients. RESULTS: There were no differences in the distribution of TCF7L2 single nucleotide polymorphism between patients and controls. However, patients with in type 1 diabetes, after adjusting for age and sex, subjects carrying C allele were at risk for a C‐peptide level lower than 0.5 nmol/L (OR 5.65 [95% CI: 1.14–27.92]) and for zinc transporter 8 autoantibody positivity (5.22 [1.34–20.24]). Participants without T allele were associated with a higher level of islet antigen‐2 autoantibodies (3.51 [1.49–8.27]) and zinc transporter 8 autoantibodies (2.39 [1.14–4.99]). CONCLUSIONS: The connection of TCF7L2 polymorphism with zinc transporter 8 and islet antigen‐2 autoantibodies and C‐peptide levels in patients supports the viewpoint that TCF7L2 is associated with the clinical signs and autoimmune characteristics of type 1 diabetes. The mechanisms of the interaction between the TCF7L2 risk genotype and anti‐islet autoantibodies need to be studied further.