Investigation of the asporin gene polymorphism as a risk factor for knee osteoarthritis in Iran.

Osteoarthritis (OA) is a degenerative disease of the joints characterized by degradation of the hyaline articular cartilage and remodeling of the subchondral bone with sclerosis. The asporin (ASPN) gene encodes a cartilage extracellular protein belonging to the small leucine-rich proteoglycan family. Polymorphisms in the aspartic acid (D) repeat region in the second exon of this gene, which consist of GAT repeats, are associated with OA susceptibility.