The main characteristics of RA are synovial hyperplasia and inflammation, the deformity of cartilage and bone, the production of anti-citrullinated protein antibodies (ACPA) or rheumatoid factors (RF), which are autoantibodies typical for RA, and systemic features, such as skeletal, pulmonary, cardiovascular and psychological disorders [29]. Here, PRTN3 is linked to rheumatoid arthritis.