In recent years, monoclonal antibodies targeting key cytokines underlying the occurrence of psoriatic skin lesions and joint involvement, i.e., Tumor Necrosis Factor-alpha (TNF-α), Interleukin 17 (IL-17), Interleukin 12 (IL-12), and Interleukin 23 (IL-23), have become more commonly used in the therapy of psoriasis. The gene discussed is IL17A; the disease is psoriasis.