Research has demonstrated that many individuals with Crohnâs ileitis share a genetic mutation that may play a significant role in disease development. A hypersensitive immuno-response to a pathogenic presence, such as bacteria, within the gastrointestinal tract is also suspected of contributing to the disease's onset.
Secondary osteoarthritis occurs less frequently than primary (also known as idiopathic) osteoarthritis. Primary osteoarthritis means that there is no known cause for the joint breakdown.
As underlying causes of osteoarthritis are discovered, the term primary, or idiopathic, osteoarthritis may become obsolete. For instance, many investigators believe that most cases of primary osteoarthritis of the hip may, in fact, be due to subtle or even unrecognizable congenital or developmental defects.