Clinical diagnosis of RA is based on the recognition of four out of seven characteristic signs and symptoms of the disease: morning stiffness of the joints lasting more than 1 h, inflammation that occurs in at least three joint areas, arthritis of the hands, symmetrical joint arthritis, rheumatoid nodules, detection of rheumatoid factor (RF), and anticitrullinated protein antibodies (ACPA) in the serum and rheumatoid nodules and changes found in radiographic examination [2,3]. Here, PRTN3 is linked to rheumatoid arthritis.