Abstract
Approximately 462 million people suffer from type 2 diabetes mellitus (T2DM) worldwide, and its prevalence is projected to increase to 7079 individuals per 100,000 by 2030. The rapid increase in the prevalence of this disease is likely a result of multiple environmental factors as increased food intake and decreased physical activity in genetically predisposed individuals. Patients with T2DM are vulnerable to developing secondary complications like retinopathy, and nephropathy. For that reason, great effort has been made to identify genes associated with T2DM. Many loci were found to be associated with T2DM risk in various populations and ethnic groups as the transcription factor 7-like-2 gene (TCF7L2) gene (rs7903146) [C/T] polymorphism locus on chromosome 10q. The TCF7L2 (rs7903146) (C/T) contributes to the disease through the Wnt/β-catenin signaling pathway affecting pancreatic islet development, expression of several genes involved in insulin granules exocytosis, and the incretin glucagon-like peptide 1 (GLP-1) gene.