Scientists have found a genetic marker that might predispose people to developing rheumatoid arthritis. The discovery could lead to a better understanding of the debilitating disease and provide clues for treatments or even cures.
Rheumatoid arthritis affects almost 400,000 people in the UK and is caused when the immune system attacks joints. The painful condition can lead to loss of mobility and disability and spread to other parts of the body including blood vessels, lungs, muscles and heart. Every year more than 12,000 people are diagnosed with the condition, for which there is no known cure. Patients are usually prescribed painkillers.
Until now two genes have been identified as explaining half of a person's genetic susceptibility to rheumatoid arthritis. The new genetic marker is thought to control the function of a nearby gene, TNAIF13.
In the Manchester University study the genetic profiles of 5,000 people with rheumatoid arthritis were compared with 3,000 control cases. The results are published today in Nature Genetics. Jane Worthington, who led the research, said it "takes us one step closer to understanding the genetic risk factors behind ... a debilitating disease for sufferers and an expensive disease for the NHS".
According to a report by the Arthritis Research Campaign, which helped fund the latest study, arthritis and its related conditions cost the NHS about £5.5bn in 1999-2000. In addition, almost £750m was spent on drugs and hip and knee replacements. Anne Barton, a clinician on the Manchester University team, said: "RA is a complex, heterogeneous disease with some people suffering inflammation of the hands and feet which comes and goes, whilst others develop a progressive form which can quite rapidly result in marked disability. We believe the genetic marker we have found may determine who develops RA or how severe the disease becomes."
Prof Worthington said that a range of therapies for rheumatoid arthritis was available but the most effective tended to be the most expensive and were only used when patients had failed on two medications. "We hope that we can use the genetic factors to predict the course of the disease. That might be a way of targeting therapies more effectively." The new marker would also help in finding new targets for drugs. "The other question is whether, in the future, we might be in a position to use this information to predict the course of a person's disease, or even whether they get it in the first place."