9 714 OMIM 180300 DiseasesDB 11506 MedlinePlus 000431 eMedicine article/331715 article/1266195 article/305417 article/401271 article/335186 article/808419 MeSH D001172 Rheumatoid arthritis ( RA ) is a chronic, systemic inflammatory disorder that may affect many tissues and organs, but principally attacks flexible ( synovial ) joints. The process involves an inflammatory response of the