Moreover, the ASAS 2009 criteria allow for verifying of the axSpA diagnosis even without the sacroiliac joint changes, based on HLA-B27 presence together with two or more characteristic clinical manifestations (inflammatory back pain, arthritis, enthesitis, uveitis, dactylitis, psoriasis, IBD, efficacy of NSAIDs, family history of spondyloarthritis, and an elevated C-reactive protein) [96,97]. This evidence concerns the gene CRP and Arthritis.