Can the arcOGEN study help future generations?
Published on 01 January 2008
arcOGEN could help future generations: pictured left to right: Bryony McCraw with 18-month-old Isla, Terry Lawrence, Eve Thomas (7), Ivy Armstrong (95), Aisha (22-months-old) and Joanna Thomas (36).
In a special feature on osteoarthritis Arthritis Today highlights the first of three important new studies which could have a major impact on treatment – now and in the future. In an exciting world first, a team of Arthritis Research UK scientists has launched a major study to search the human genome for genetic risk factors for osteoarthritis.
The aim of the arcOGEN study is to identify the genetic changes, known as polymorphisms, which increase the risk of people developing osteoarthritis. Arthritis Research UK expects that this could lead to several potential breakthroughs such as genetic tests becoming available to predict who is likely to develop osteoarthritis, particularly at a young age, and how severely. Ultimately it could lead to new drugs that could slow down disease progression and even prevent osteoarthritis occurring.
The largest study of its kind ever undertaken, it will involve screening the DNA of 8,000 people suffering from osteoarthritis of the hip and knee and 6,000 healthy people to compare the differences.
The two-year study will be funded by a grant of £2.2m – the largest single grant ever awarded Arthritis Research UK.
Osteoarthritis is the number one cause of mobility problems in the elderly
Osteoarthritis (OA) can affect any joints but involvement of the knee and hip is the number one cause of mobility problems in the elderly population. Despite its high prevalence there is no effective drug treatment to control the progression of osteoarthritis, and currently available painkillers carry a high risk of side-effects.
Wrongly thought of as an inevitable consequence of ageing, osteoarthritis is a disease in its own right but the reasons why some people do, and some do not, develop the disorder are unclear.
“Osteoarthritis is an extremely debilitating disease characterised by joint pain and reduced mobility, and is the biggest cause of disability in older people bar none,” explained Dr John Loughlin, principal investigator of the arcOGEN study.
“Genetic factors play a major role in the development of osteoarthritis and identifying them will help us to understand why the disease occurs and will assist in the development of new treatments by identifying new molecular targets. We have brought together all the major OA genetics research groups within the UK and experts in human genetics to enable us to perform the definitive search of the human genome for osteoarthritis genetic risk factors.”
arcOGEN – the most important study Arthritis Research UK has ever funded
According to Professor Alan Silman, Arthritis Research UK medical director, arcOGEN could be the most important study the charity had ever funded and could have far-reaching consequences in terms of better understanding of the disease and identifying new treatment targets.
“Compared with many other conditions where scientists have looked for a genetic basis, there is a very strong belief that osteoarthritis is genetically-based because there are many families which have osteoarthritis running through the generations,” he said. “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.”
It is known that there is a considerable genetic component to osteoarthritis, and those people with a parent or sibling with the condition are two to three times more likely to develop OA than those who don’t. However, there are also other risk factors such as obesity, a sports injury or a heavy manual occupation. It may become possible for medics to perform a genetic-risk profile alongside a lifestyle-risk profile to determine the overall risk, and then offer treatment or advice on how the risk could be reduced.
Insights for new treatment
Another leading member of the consortium, Professor Tim Spector, said that the consortium’s investigation of the DNA of 8,000 patients would provide it with “unprecedented power.” The results would be made freely available as an international resource that could be mined for insights into new treatments. The outcome of the genome screen is likely to be of considerable interest to pharmaceutical companies wanting to develop new drugs to prevent the onset of osteoarthritis. Identifying predisposing genes will point out new biological pathways to target.
The arcOGEN team hope to find between 10 and 20 of the genes that could have a strong to moderate risk for osteoarthritis, although there may be many more. Human DNA contains about 30,000 genes, with millions of polymorphisms, which will all be checked by sampling patients’ DNA taken from their white blood cells.
Genetics experts in London, Manchester, Southampton, Nottingham, Edinburgh, Newcastle and Cambridge form part of the UK-wide collaborative project.
"I’ve got arthritis, my mother has arthritis, and I don’t want my daughters and granddaughters to get it too."
Terry Lawrence knows better than most how heredity plays a significant role in developing osteoarthritis (OA) – and is desperate that her daughters and granddaughters don’t suffer in the same way that she and her mother have.
Now 62, Terry, from Bromsgrove in Worcestershire, developed osteoarthritis of the knee while in her fifties, and she has had a knee replacement. The condition has now spread to other large joints in her body and she is now on the waiting list for a shoulder replacement. Hip replacement surgery has also been pencilled in for 18 month’s time.
Terry’s mother Ivy Armstrong, now 95, also has severe osteoarthritis. She had a hip replacement and spinal disc fusion in her eighties.
Terry’s greatest wish is that daughters Joanna, who is 36, and 34-year-old Bryony, and their own young daughters, Isla, Eve and Aisha, avoid a similar fate. But with heredity a major causal factor in developing the condition, until recently she had little hope of this.
arcOGEN – a lifeline
However, she believes that the new arcOGEN study may offer a lifeline if not for her daughters, then for her granddaughters. “I’m very anxious to identify whether my daughters and granddaughters might develop osteoarthritis, and identifying the relevant genes and initiating early preventative treatment might alleviate some of the pain and restriction that I am experiencing, and improve their quality of life as they get older,” she says.
"I am so worried that they may get to the stage in life that I’m at and things start breaking down. If there is any legacy that I could leave them it would be that they don’t get osteoarthritis, and if there was anything I could do, I’d do it to prevent this happening."
Read Terry Lawrence's story on her family's experiences with osteoarthritis.