There is compelling evidence that RORγt represents an attractive drug target based on its critical involvement in the regulation of the Th17/IL-17 pathway that plays a pivotal role in the pathogenesis of several autoimmune disorders, including psoriasis, ankylosing spondylitis, multiple sclerosis, uveitis and rheumatoid arthritis [1–3]. This evidence concerns the gene IL17A and ankylosing spondylitis.