Transcription Factor 7-Like-2 (TCF7L2) rs7903146 (C/T) Polymorphism in Patients with Type 2 Diabetes Mellitus

Abstract

Background Type 2 diabetes mellitus (T2DM) is a heterogeneous group of metabolic disorders characterized by the incapability of pancreatic beta cells to increase insulin secretion to compensate for insulin resistance in the peripheral tissues. T2DM is a multi-factorial disease including several environmental factors with the presence of genetic predisposition. The transcription factor 7-like-2 gene (TCF7L2) rs7903146 (C/T) polymorphism is one of the most susceptible genes to T2DM discovered to date, with contribution 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. Aim of the Work In this study we aimed to investigate the potential association of the transcription factor 7-like-2 (TCF7L2) rs7903146 (C/T) gene polymorphism in patients with type 2 diabetes mellitus. Patients and Methods The study was a case- control study conducted on 70 T2DM patients recruited from the endocrinology clinic at Ain Shams University Hospitals, and 30 non diabetic healthy controls matched with the patients in age and sex. All subjects underwent full history taking, thorough clinical examination, routine laboratory investigations including haemoglobin A1c (HbA1c), lipid profile; total cholesterol (TC), triglycerides (TG), high density lipoprotein-cholesterol (HDL-C) and low density lipoprotein-cholesterol (LDL-C) and determination of TCF7L2 gene polymorphism by real-time quantitative polymerase chain reaction (RT-PCR). Results The minor T allele of the rs7903146(C/T) SNP was associated with high risk of development of T2DM with an OR of 1.35 (95% CI: 0.68-2.6), the heterozygous genotype (CT) with an OR 1.16 (95% CI: 0.49-2.7) and the homozygous mutant genotype (TT) with OR of 3.16 (95% CI: 0.15-6.31), however, they were statistically insignificant (p-value >0.05). Conclusion Our study did not confirm the presence of significant association between the TCF7L2 rs7903146(C/T) polymorphism and T2DM, however, it pointed to the possibility of presence of high risk of development of T2DM in patients with TT genotype. Further studies with higher sample size are needed to clarify the association.