Single Nucleotide Polymorphism (SNPs) Of TCF7L2 Gene with Susceptibility to Type 2 Diabetes in Vokkaliga Community of Mysuru

Background: Transcription factor 7-like 2(TCF7L2) variants have been associated with Type 2 Diabetes Mellitus in multiple ethnic groups. Specifically associated variants increase the risk of T2DM 1.5-fold in a heterozygote and 2.4-fold in homozygote, corresponding to a population attributable risk of 21%. This makes TCF7L2 variants the strongest known genetic risk factors for T2DM. The present study aimed to identify for the first time the single nucleotide polymorphism in the TCF7L2 gene in T2DM subjects between the age group of 40-55 years in the Vokkaliga community of Mysuru, Karnataka and also to investigate the potential association of this polymorphism with glucose metabolism and HbA1c levels. The study also aimed at comparing the physical parameters such as Body Mass Index (BMI), height, weight etc. in diabetic and non-diabetic groups. Materials and methods: The study included a total of 130 subjects in which 71 were diabetic and 59 were non-diabetics aged between 40-55 years of Vokkaliga community of Mysuru. Their BMI was calculated based on their height, weight, and waist to hip ratio. The venous blood samples were collected and the random blood sugar (RBS) and glycated hemoglobin (HbA1c) was estimated. DNA was extracted from blood and genotyped by Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) with specific primers to amplify the fragment for digestion with a restriction enzyme (Rsa1). Statistical analysis was done by the Multifactor Dimensionality Reduction (MDR) method and the physical parameters were compared. Results: RBS and HbA1c showed a statistically significant difference between the diabetic and non-diabetic groups (p= <0.001, p= <0.0018) respectively. An amplification product of 201bp was obtained which was further used for detecting the polymorphism by the RFLP method. However, the polymorphism was not detected in T2DM patients belonging to this community. Conclusions: The results showed no significant correlation between the TCF7L2 gene polymorphism and T2DM in the Vokkaliga community of Mysuru. The lack of association might have come from the small sample size. Further studies relating TCF7L2 gene polymorphism and T2DM with larger sample size must be explored in order to confirm the observed finding.