Scientists have identified eight regions of the genetic code associated with an increased risk of developing osteoarthritis.
The most common form of arthritis, osteoarthritis is a disease of the joints where the cartilage breaks down. According to the American College of Rheumatology, 70 percent of people over the age of 70 have X-ray evidence of osteoarthritis and half of them will have symptoms.
Researchers at Newcastle University looked
at the DNA of 7,400 patients with severe hip and knee osteoarthritis and
compared it with that of 11,000 healthy people.
This first analysis allowed the scientists to focus their attention on particular 'culprit' sections of the DNA.
They repeated the comparison with the DNA of a further 7,500 osteoarthritis patients and more than 43,000 unaffected people from the Netherlands, Estonia, Iceland and the UK.
Their results confirmed the three previously reported genes linked to osteoarthritis and identified a further eight. Five of these were significantly associated with the disease. The strongest association was in the region of the GLN3 gene, which is involved in cell maintenance. Another three were located on genes important for cartilage, bone development and body weight.
'We know that osteoarthritis runs in families and that this is due to the genes that people pass on, rather than their shared environment', said Professor John Loughlin, who led the research.
that the study allowed researchers to say with a high degree of confidence
which genetic regions were the major risk factors. '[It's] the first time that
this has been possible for this common yet complex disease', he said. 'It's an
important first step'.
Professor Alan Silman, medical director at Arthritis Research UK (the charity that funded the work), called the study 'a major breakthrough in our understanding of osteoarthritis, which we hope will help us to unlock the genetic basis of the disease'.
'Until we understand the cause of this complex disease', he added, 'we cannot hope to find a cure'.