Researchers have pinpointed 42 new areas in DNA that increase the risk of rheumatoid arthritis.
The results came from the largest genetic study ever carried out, involving nearly 30,000 patients. The findings are published in the Journal Nature.
The research team compared the DNA of arthritis patients with those without the disease and found 42 'faulty' areas that were linked with the disease. A BBC science correspondent says the hope is that drugs can be developed to compensate for these faults.
Professor Robert Plenge of Harvard Medical School found that one of these areas produced a weakness that was treated by an existing drug that was developed by trial and error, rather than specifically made to correct the genetic problem.
This, he said, shows such discoveries could be used to design new drugs.
"What this offers in the future is an opportunity to use genetics to discover new medicines for complex diseases like rheumatoid arthritis to treat or even cure the disease," he said.
The study also found SNPs in rheumatoid arthritis patients that also occur in patients with types of blood cancer.
"There are already therapies that have been designed in the cancer field that might open up new opportunities for retargeting drugs," Professor Jane Worthington of the centre for genetics in Manchester told BBC News.
"It might allow us a straightforward way to add therapies we have to treat patients with rheumatoid arthritis".
