Visfatin acts as a pro-inflammatory mediator, with the ability to induce matrix metalloproteinase (MMP)-9 and NF-κB in monocytes and in human endothelial cells, which plays an important role in the pathogenesis of vascular inflammation in obesity and type 2 diabetes, and leads to atherosclerotic plaque instability. The gene discussed is NAMPT; the disease is obesity due to melanocortin 4 receptor deficiency.