CD226 and rheumatoid arthritis: The role of DNAM-1 in AS is unknown, although there have been several reports associating single nucleotide polymorphisms (SNPs) in the DNAM-1 gene with different autoimmune pathologies such as Type 1 diabetes mellitus (T1D), multiple sclerosis (MS), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE) [13,14,15,16].