In particular, IL-17 is able to synergize with TNF-α, IL-22, and other cytokines, including IL-6 and IL-8, in sustaining the inflammatory process at different sites and in favoring the development of comorbidities that are typical of psoriasis, such as PsA, metabolic syndrome, obesity, and cardiovascular disease. This evidence concerns the gene IL17A and obesity due to melanocortin 4 receptor deficiency.