GENETICS AND ARTHRITIS
Arthritis literally means inflammation of a joint. It is more commonly known as wearing out of our joints. When arthritis occurs, cartilage (which is the material that covers the ends of the bones) begins to wear leading to inflammation and pain.
There is strong evidence that Osteoarthritis (OA) is genetically linked. Classic twin studies have shown that the influence of genetic factors is between 39% and 65% in radiographic OA of the hand and knee in women, about 60% in OA of the hip, and about 70% in OA of the spine. Taken together, these estimates suggest a heritability of OA of 50% or more, indicating that half the variation in susceptibility to disease in the population is explained by genetic factors.
Osteoarthritis (OA) or degenerative joint disease (DJD) is the most common type of arthritis. OA and DJD are not autoimmune diseases and, therefore, are unlikely to share the same genes as ankylosing spondylitis, rheumatoid arthritis or SLE(Lupus).
In a study comparing identical to non-identical twins, an identical twin had a two-fold higher chance of developing OA of the hand or knee if the other twin had the same disease. This indicates genetics may play an important role in the development of OA or DJD.
Another study investigating the role of genetics in OA of the hand showed that sisters of women with this disease had a two-fold increased risk of developing hand OA when compared to the general population. This risk was increased by five- to seven-fold if the diseased sibling had severe disease. Certain gene mutations have been linked only to a particular site of OA (e.g., knee, hip or hand) implying that each site might have its own genetic basis.
These recent findings about the genes contributing to the many forms of arthritis are leading to new knowledge about their cause, as well as new treatment strategies to reduce pain and crippling, and possible means of disease prevention.