IBD: inflammatory bowel disease, CD: Crohn’s disease, UC: ulcerative colitis, SAPHO: synovitis, acne, pustulosis, hyperostosis, and osteitis, PPP: palmoplantar pustulosis, HS: hidradenitis suppurativa, CT: computed tomography, MRI: magnetic resonance imaging, NA: not available or not applicable, IV: intravenous, TNF: tumor necrosis factor, IL: interleukin, ACW: anterior chest wall, NSAID: nonsteroidal anti-inflammatory drug. The gene discussed is TNF; the disease is ulcerative colitis.