A permeable intestinal epithelium (increased intestinal permeability or disrupted intestinal barrier) can allow bacteria and bacterial components like lipopolysaccharides from the gut to enter the bloodstream (i.e., endotoxemia), triggering chronic low-grade inflammation, potential insulin resistance, and obesity, all of which are key factors in MetS progression [49]. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.