A genetic factor in the development of osteoarthritis and clues to its mechanism of action have been described by Japanese researchers in the January 2 online edition of Nature Genetics (http://www.nature.com/naturegenetics).
The researchers found a strong association between an allele (D14) of the gene encoding asporin, an extracellular matrix protein, and the presence and severity of hip and knee osteoarthritis. They also found that in an in vitro model, asporin inhibits cartilage formation in the joint by suppressing tumor growth factor 
–mediated expression of the genes that encode aggrecan and type 2 collagen and by reducing proteoglycan accumulation.
The researchers hypothesize that asporin may play a major role in cartilage matrix homeostasis in adults by modulating tumor growth factor and that too much inhibition of this growth factor caused by the disease-associated allele may speed the progress of osteoarthritis. Further research to elucidate . . . [Full Text of this Article]
