Compared with CIA WT mice with mild arthritis, CIA Mir204/Mir211 dKO mice displayed severe arthritis, as manifested by synovial hyperplasia along with angiogenesis and cartilage destruction (Figure 8B), suggesting that loss of Mir204/Mir211 deteriorates RA and Mir204/Mir211 may play a protective role in RA development. This evidence concerns the gene MIR211 and arthritic joint disease.