COMP and rheumatoid arthritis: In fact, ADAMTS-12 participation in arthritic processes has been mainly related to its ability to degrade COMP because fragments generated following its cleavage were found in diseased cartilage, synovial fluid and in serum of patients with knee injuries, osteoarthritis and rheumatoid arthritis (Neidhart et al., 1997; Dickinson et al., 2003; Lin and Liu, 2009).