Eight new genetic links to osteoarthritis have been uncovered that could help scientists develop better treatments for the disease.
Previously, only three genetic variants associated with osteoarthritis were known. Yet inherited factors are believed to contribute to 60% of differences in the risk of suffering the disease.
Osteoarthritis, progressive damage to the joints caused by general wear and tear or injury, can result in debilitating levels of stiffness and pain. It affects around 40% of people over the age of 70.
The researchers began by looking at the complete genetic codes of more than 7,400 patients with severe hip and knee osteoarthritis.
Their DNA was compared with that of more than 11,000 healthy individuals.
Once the most promising genetic sites were identified, the study was repeated by comparing the genomes of another 7,500 people with a much bigger healthy population of 43,000.
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The results confirmed the three previously reported gene variants and found a further eight linked to osteoarthritis.
Five of the new variants were significantly associated with the disease.
The one with the strongest effect was situated in the region of the GNL3 gene which produces a protein with an important role in cell maintenance.
Three others were in areas of DNA encoding proteins involved in the regulation of cartilage, bone development and body weight.
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The findings are published today in the latest online edition of The Lancet medical journal.
Study leader Professor John Loughlin, from the University of Newcastle, said: "The health economic burden of osteoarthritis is increasing commensurate with obesity prevalence and longevity. Our findings provide some insight into the genetics of arthritis and identify new pathways that might be amenable to future therapeutic intervention."
Commenting on the research in the journal, Dr Marc Hochberg and colleagues from the University of Maryland in Baltimore, US, wrote: "The challenge will be to connect the biology of these genes to the development and progression of osteoarthritis and to investigate the therapeutic potential of these pathways for disease prevention and treatment."
The research was funded by the British charity Arthritis Research UK.
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