MAPK (Mitogen-activated protein kinase) is a family of serine-threonine protein kinases that can be activated by different extracellular stimuli and cell adhesion, including four subfamilies: ERK, P38, JNK, and ERK5, and it is significant in the pathophysiological process of obesity (31). This evidence concerns the gene MAPK8 and obesity due to melanocortin 4 receptor deficiency.