IL17A and obesity due to melanocortin 4 receptor deficiency: In addition, other genes predispose to psoriasis but are directly linked to inflammation, such as interleukins IL-1, IL-6, IL-8 [62], IL-12B, IL-22, IL-23A, IL-23R, IL-2, IL-21, IL-17 [39], vascular endothelial growth factor (VEGF) and interferon-γ25, many of which presenting an altered expression in obesity too.