NAMPT and obesity due to melanocortin 4 receptor deficiency: We have also demonstrated how insulin resistance, the first step in obesity associated impairment of carbohydrate metabolism, enhances these changes in the degree of expression of specific isoforms of proteins related to inflammation (haptoglobin) and metabolism (ApoA1), some of them correlating with serum levels of adipokines, such as IL-6 and NAMPT/visfatin, with a known role in IR.