Aside from chronic inflammation, these conditions are all characterized by ankylosis, stiffness and fusion of bone in the spine and peripheral joints, prooked by abnormal cartilage and bone formation.

• 除去慢性炎症，当异常软骨和骨形成时，这些疾病都很表现出关节强直，四肢强直，脊柱和周围关节融合