A literature search was performed to find studies thatinvestigated associations between TYK2 SNPs and autoimmunediseases (multiple sclerosis, systemic lupus erythematosus, Crohn’s disease,ulcerative colitis, psoriasis, rheumatoid arthritis, type 1 diabetes, andinflammatory bowel disease). The gene discussed is TYK2; the disease is Crohn disease.