,2 Given that TYK2 belongs to the Janus kinase (JAK) family that exerts effects on a wide range of inflammatory disorders, TYK2 inhibitors may have the potential in the treatment for other autoimmune diseases, such as inflammatory bowel disease,3 rheumatoid arthritis,4 and type 1 diabetes.5 This evidence concerns the gene TYK2 and rheumatoid arthritis.