Association of TCF7L2 rs12255372 –G/T polymorphism with type 2 diabetes in a Nigerian population
Polymorphisms of the transcription factor 7–like 2 (TCF7L2) gene have been associated with susceptibility to type 2 diabetes (T2D) in various ethnic populations, but have not been previously studied in a Nigerian population. We investigated the relationship between the TCF7L2 rs12255372 (G/T) polymorphism and type 2 diabetes (T2D) in a Nigerian population. This was a preliminary case–control study that included 73 T2D patients and 75 non-diabetic (ND) controls. Following blood collection, fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), high density lipoprotein-cholesterol (HDL-c) and low density lipoprotein-cholesterol (LDL-c) were assayed. PCR-Restriction Fragment Length Polymorphism (RFLP) was employed to molecularly genotype for the TCF7L2 G/T polymorphism using the MluCI restriction enzyme. The GG homozygote genotype was more frequent in ND controls (38.5%) than in T2D patients (23%) while the TT genotype was more frequent in T2D patients (25.7%) than in ND controls (11.5%). Thus, the TCF7L2 G/T polymorphism was associated (P < 0.05) with T2D. The recessive model showed the greatest risk of T2D when the TT genotype was compared to the GX (GG+GT) genotype (odds ratio (OR): 3.91; 95% confidence interval (CI): 1.93-7.96, P < 0.001). The FBG and HDL-c were significantly different (P < 0.05) in subjects with the mutant (GT and TT) genotypes compared to the GG genotype. In conclusion, the TCF7L2 G/T polymorphism was associated with increased risk of T2D in a Nigerian population. This variant could affect pathophysiological markers associated with risk of T2D. Further studies are needed in other populations in Nigeria to confirm the effects of this polymorphism on pathophysiological markers of T2D.