Researchers have discovered DNA variations at five new gene locations that are associated with development of Parkinson's disease, according to a new study.

Only six other gene variant locations have so far been identified and associated with Parkinson's disease risk, the study said.

Of the 11 variant locations now known to scientists, the 20 percent of people with the most variants are 2.5 times more likely to develop Parkinson's disease than the 20 percent of people with the fewest variants, according to the study.

"This study provides evidence that common genetic variation plays an important part in the cause of Parkinson's disease ," researchers from the National Institutes of Health, University College London and the International Parkinson Disease Genomics Consortium said in a statement.

Researchers discovered the five additional high-risk variant locations by analyzing five genome-wide association studies from the United States and Europe. The studies included 12,386 people with Parkinson's disease and 21,026 healthy people, with 7.7 million possible genetic variants.

Before 2007, when the first six high-risk variant locations were discovered, scientists thought environmental factors were wholly responsible for Parkinson's disease, the researchers said. This new finding provides more evidence that there is also a strong genetic component to the disease.

More study is needed before the roles these new variant locations play in risk for the disease are known, they said, but the data highlight new genes to focus on that are linked with development of Parkinson's disease.

The study was published online Feb. 1 in the journal Lancet.

Pass it on: Scientists now know of 11 gene locations with variations that seem linked with an increased risk of Parkinson's disease.

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