SLC2A4 and metabolic syndrome: Obese individuals have a higher serum level of IL-6, which is correlated with the development of metabolic syndrome, insulin resistance, and T2DM (Juge-Aubry et al., 2005) due to the capability of IL-6 to downregulate the gene expression of GLUT-4 and IRS-1 (Rotter et al., 2003).