Molecular Effect of Variants in Toll-like Receptor 4 Gene in Saudi Patients with Type 2 Diabetes Mellitus

Single-nucleotide polymorphisms (SNPs) in the Toll-like receptor 4 (TLR4) gene have been documented in type 2 diabetes mellitus (T2DM) and other diseases in the Saudi population. We investigated the relationship between rs11536889, rs4986790, and rs4986791 SNPs in the TLR4 gene and T2DM in the Saudi population; 105 patients with T2DM and 105 healthy controls were analyzed. The TLR4 gene was amplified through PCR, followed by restriction fragment length polymorphism analysis for rs4986791 and Sanger sequencing for rs11536889 and rs4986790 SNPs. The clinical and biochemical characteristics were associated with T2DM (p < 0.05). The rs11536889, rs4986790, and rs4986791 SNPs in control subjects followed the Hardy-Weinberg equilibrium (p > 0.05). Alleles were associated with rs11536889, rs4986791, heterozygous codominant, and dominant models (p < 0.05). However, the rs4986790 SNP was not associated with T2DM (p > 0.05). Logistic regression analysis showed that high-density lipoprotein cholesterol (HDLc) levels were associated with T2DM (p < 0.001). Analysis of variance showed that waist (p = 0.0005) and hip circumferences (p = 0.002) in rs4986790 and rs4986791 SNPs, in SBP (p = 0.001), DBP (p = 0.002), and HDLc levels (p = 0.003), were associated with T2DM subjects. T2DM was also associated with the haplotype (p < 0.001) but not with linkage disequilibrium. The gene-gene interaction was associated with the three SNPs studied in patients with T2DM according to the generalized multifactor dimensionality reduction model (p < 0.0001). Dendrogram and graphical depletion analysis revealed a moderate association in patients with T2DM. The results suggest that rs11536889 and rs4986790 SNPs are genotypically and allelically associated with T2DM in Saudi patients. Future functional studies are recommended to validate the genetic roles of these SNPs in the pathogenesis and progression of diseases.