FGF21 and obesity due to melanocortin 4 receptor deficiency: This deregulation of adipokines is exemplified by the direct and positive association between insulin resistance, diabetes, and obesity-related diseases with some adipokines, like leptin, vaspin, and visfatin, and an inverse association between those diseases and other adipokines, like omentin-1, adiponectin, and FGF-21 (Blüher, 2014; Fève et al., 2016).