Image caption Current treatments relieve the symptoms but not for all patients, and there is no cure

An international team of researchers has found more than 40 new areas in DNA that increase the risk of rheumatoid arthritis.

The work is the largest genetic study ever carried out, involving nearly 30,000 patients.

The investigators believe new drugs could be developed to target these areas that could one day provide a cure for the disease.

The findings are published in the Journal Nature.

What this offers in the future is an opportunity to use genetics to discover new medicines for complex diseases like rheumatoid arthritis and to treat or even cure the disease Prof Robert Plenge, Harvard Medical School

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. The hope is that drugs can be developed to compensate for these faults.

The lead researcher 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 finding, he says, 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.

Complex diseases

Some have argued identifying genetic weak areas for complex diseases - known as single nucleotide polymorphisms (SNPs) - is not useful. There is little or no evidence, they argue, that "silencing the SNPs" with drugs will relieve any symptoms.

But Dr Plenge says the fact that he has found an established drug that treats the symptoms that arise from a particular SNP for rheumatoid arthritis validates this genetic approach.

There are already therapies that have been designed in the cancer field that might open up new opportunities for retargeting drugs Prof Jane Worthington, Director, Centre for Genetics

"It offers tremendous potential. This approach could be used to identify drug targets for complex diseases, nut just rheumatoid arthritis, but diabetes, Alzheimer's and coronary heart disease"

Fast track

The study also found SNPs in the rheumatoid arthritis patients that also occur in patients with types of blood cancer.

According to Prof Jane Worthington, director of the centre for genetics in Manchester, this observation suggests that drugs that are being used to treat the cancer could be effective against rheumatoid arthritis and so should be fast tracked into clinical trials.

"There are already therapies that have been designed in the cancer field that might open up new opportunities for retargeting drugs," she told BBC News.

"It might allow us a straightforward way to add therapies we have to treat patients with rheumatoid arthritis".

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