FGF21 and obesity due to melanocortin 4 receptor deficiency: Different alterations in adipokines, myokines, osteokines, hepatokines, and inflammatory cytokines have been described in patients with obesity and this may be related to the development of other metabolic diseases [5,6], especially regarding the adipokine adiponectin, the osteokine OCN, the myokine irisin, the hepatokine FGF-21, and the inflammatory cytokine MCP-1 [1].