Carriers of the TCF7L2 rs7903146, rs12255372 Risk Alleles in the South Tamil Nadu T2DM Patients Present with Early Incidence and Insulin Dependence

BACKGROUND AND AIMS: Metabolic abnormalities in T2DM (Type 2 diabetes mellitus) include classic manifestations such as impaired insulin secretion, synthesis and peripheral insulin resistance. The intronic variants rs7903146 and rs12255372 of the TCF7L2 (transcription factor 7-like 2) gene are strongly associated with risk of incidence of T2DM and impaired β-cell functions. Studies addressing the early T2DM onset, and early insulin dependence in T2DM patients of south Tamil Nadu are still lacking, and hence the present study focuses in determining the influence of the TCF7L2 polymorphisms in the incidence and disease course in the T2DM patients of south Tamil Nadu. METHODS: Anthropometric measurements and biochemical parameters were carried out in early onset (Group A), early onset insulin dependent T2DM patients (Group B) and non-insulin dependent T2DM patients (Group C). PCR, allele specific PCR (ASP), PCR product sequencing strategies were utilized to determine the genotype and the impact of the TCF7L2 SNPs in the T2DM disease course. RESULTS: Female T2DM patients with the CT/TT rs7903146 genotype (P = 0.005) and the rs12255372 GT/TT genotype (P = 0.036) exhibited a significantly low mean age for T2DM incidence. Correlation/regression analysis in the T2DM patients revealed that rs12255372 (P = 0.042) is associated with early onset in the Group C patients and the rs7903146 (P = 0.018), rs12255372 (P = 0.026) are associated with insulin dependence in the group B patients. CONCLUSION: Screening for the TCF7L2 polymorphisms will prevent T2DM incidence and enable life style changes, appropriate therapeutic strategies that would help combat the accelerated disease course in the T2DM patients.