Recent studies have found that ADAMTS-5 and -9 play an important pathological role in matrix degeneration; for example, ADAMTS-5 contributes to intervertebral disc and articular cartilage degeneration [10, 11, 17–20], and ADAMTS-9 contributes to arthritis, breast cancer metastasis, and central nervous system pathologies [10, 15, 21, 22]. The gene discussed is ADAMTS9; the disease is arthritic joint disease.