Polymorphisms (rs10440635 and rs76523431) in PTGER4 loci were associated with increased PTGER4 gene expression in synovial biopsy samples from patients with spondyloarthritis but also the susceptibility and severity of AS (Evans et al., 2011; Chai et al., 2013). The gene discussed is PTGER4; the disease is spondyloarthropathy.