Tumor necrosis factor-α inhibitors (TNFi) were the first class of biologic disease-modifying anti-rheumatic drugs (bDMARDs) that were used in patients with rheumatic diseases, and they are currently licensed for different types of inflammatory diseases including rheumatoid arthritis (RA), spondyloarthropathies (SpA), inflammatory bowel disease (IBD) and psoriasis. This evidence concerns the gene TNF and rheumatoid arthritis.