New study to probe genetics of osteoarthritis

A UK study, announced this week, aims to identify 20 genes involved in osteoarthritis (OA): the most common form of arthritis. Researchers are hopeful that their work will lead to a cheap diagnostic test and new targets for treatment for the disorder that currently has no cure.

The Arthritis Research Campaign has raised £2 million for a two-year study, which will be performed at eight centres around the UK. Scientists will perform a 'whole genome association' study, looking at 500,000 SNPs - so-called DNA sequence variants - in 6,000 healthy people and 8,000 who have had or are awaiting join replacement surgery due to OA, looking for differences between the two groups.

Despite being conventionally seen as an unavoidable product of old age, genetics is believed to play a central role in the development of osteoarthritis. People with a parent or sibling with osteoarthritis are two to three times more likely to develop osteoarthritis.

Similar studies have recently identified genes in disorders as diverse as rheumatoid arthritis, prostate cancer and neonatal diabetes, but not on the scale the directors of this research are predicting.

'Compared with many other conditions where scientists have looked for a genetic basis, there is a very strong belief that OA is genetically-based because there are many families which have OA running through the generations', said Professor Alan Silman, medical director of the Arthritis Research Campaign. 'Until now we didn't know what that genetic basis was, but now we have the modern technology we have a unique opportunity to unlock the genetic code', he added.

Osteoarthritis, most commonly seen in those over 65, is caused by cartilage breakdown in joints leading to pain and swelling. It is the primary cause of disability in the elderly: affecting around 2 million people in the UK.

A predictive test, which the project leaders hope will cost as little as £10, will allow potential sufferers to make certain lifestyle changes - such as weight loss - to minimize the risk of developing the disorder as well as alert them to the necessity or early medication.

Professor Tim Spector, genetic epidemiologist from St Thomas's Hospital, London, a member of the research consortium, said: 'We're really on the edge of a brave new era in osteoarthritis. These genes can tell us who is going to do badly, and also tell us about new pathways'.