10 May 2005
Osteoarthritis, the most common form of arthritis and the most frequent cause of joint disease, affects more than 5% of all adults worldwide. The disease involves the progressive loss of cartilage around the joints, leading to pain and dysfunction; the joints are normally protected by the balanced production and degredation (homeostasis) of cartilage extracellular matrix (ECM) components. If cartilage is degraded more rapidly than new tissue is formed, the ends of bones that meet in joints are inadequately protected and can rub together, causing inflammation. Osteoarthritis is known to be a polygenic disease influenced by both genetic and environmental factors. A Japanese study published in Nature Genetics identifies a new association between a gene and susceptibility to osteoarthritis, and also provides evidence of the functional link between mutations in the gene and development of the disease [Kizawa H et al. Nat Genet. 2005; advance online publication].
Researchers from Japan's Institute of Physical and Chemical Research (RIKEN) looked at the ASPN gene, which encodes asporin, a recently identified ECM protein that binds to TGF-