"Unravelling the genetic underpinnings of Parkinson's is vital to understanding the multiple mechanisms involved in this complex disease, and hopefully, may one day lead to effective therapies," said Andrew Singleton, a scientist at the US National Institutes of Health's National Institute on Aging (NIA) and senior author of the study.
Singleton and his colleagues collected and combined data from existing genome-wide association studies (GWAS), which allow scientists to find common variants, or subtle differences, in the genetic codes of large groups of individuals.
The combined data included approximately 13,708 Parkinson's disease cases and 95,282 controls, all of European ancestry.
The investigators identified potential genetic risk variants, which increase the chances that a person may develop Parkinson's disease.
Their results suggested that the more variants a person has, the greater the risk, up to three times higher, for developing the disorder in some cases.
The researchers confirmed the results in another sample of subjects, including 5,353 patients and 5,551 controls.
By comparing the genetic regions to sequences on a state-of-the-art gene chip called NeuroX, the researchers confirmed that 24 variants represent genetic risk factors for Parkinson's disease, including six variants that had not been previously identified.
The NeuroX gene chip contains the codes of approximately 24,000 common genetic variants thought to be associated with a broad spectrum of neurodegenerative disorders.
Some of the newly identified genetic risk factors are thought to be involved with Gaucher's disease, regulating inflammation and the nerve cell chemical messenger dopamine as well as alpha-synuclein, a protein that has been shown to accumulate in the brains of some cases of Parkinson's disease.
The study was published in the journal Nature Genetics.