PRTN3 and rheumatoid arthritis: The pathogenesis of RA is complex and not fully understood, but it is known that autoimmunity (developed by adaptative immune system) begins years before clinical symptoms appear, marked by the production of autoantibodies such as anti-citrullinated protein antibodies (ACPA), anti-carbamylated protein antibodies (anti-CarP) and rheumatoid factor (RF) [5].