TBX21 and rheumatoid arthritis: According to several case-control studies, various SNPs have shown association with other immune-related diseases, especially in the promoter region upstream of this gene.14-16 Between upstream promoter variants, -1993T>C and -1514T>C polymorphism were the most significant in association with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).14,17 Consequently, there seems to exist a possible relationship between TBX21 gene promoter region SNPs and MS disease, which has not been inspected so far.