Researchers have discovered a common gene which links Parkinson's sufferers around the world.
The scientists, from the Mayo Clinic in Jacksonville and the National Taiwan University Hospital in Taiwan, found that Chinese people with the LRRK2 gene mutation were over twice as likely to develop the disease than non-carriers.
While they concluded that those with the gene were more at risk of Parkinson's, they said not everyone with the mutation develops the disease and, when people do, it is probably as a result of other genetic and environmental factors.
Lead author Matthew Farrer, a neuroscientist from the Mayo Clinic, claimed the discovery was a small step in revolutionising genetics in medicine.
Other studies have found one of the mutations, G2385R, is more common in Asian patients with Parkinson's disease than those without.
According to the Parkinson's Disease Society, around 120,000 individuals have the disease.