Articles from PubMed were obtained using the search terms “Demyelinating Disease,” “Multiple Sclerosis,” “Optic neuritis,” and “Tumor Necrosis Factor-α.” Including our 4 patients, 122 cases with CNS demyelinating events during anti-TNF-α treatment were identified: 69 case reports and 53 cases from the Spanish Registry of biological therapies in rheumatic diseases and an adverse event data base [30, 49, 50, 56, 60–90, 91•, 92••, 93]. This evidence concerns the gene TNF and multiple sclerosis.