PARN and ulcerative colitis: By these similar methods, Zhang et al.16 found that the MAPK signaling pathway may be associated with both pathogenesis of ankylosing spondylitis and ulcerative colitis and that poly(A) specific ribonuclease subunit PAN3 Gene (PAN3) may be a potential diagnostic marker for patients with ulcerative colitis complicated by ankylosing spondylitis.