ERAP1 and ankylosing spondylitis: Regarding the non-HLA region, different relevant genes for the development of autoimmunity processes were suggested as shared risk factors for LVV, including NOS2, ERAP1, REL and PRKQC, which have been associated with psoriasis, Behçet disease, ankylosing spondylitis (AS), and rheumatoid arthritis, amongst others20, 21, 22.