NIH Scientists Discover 6 New Genetic Risk Factors Involved in Parkinson's Disease

By C. Rajan, contributing writer

A recent study led by scientists working in NIH laboratories has identified six new genetic risk factors that are involved in Parkinson's disease. The study has been published in the July 27 issue of Nature Genetics.

Scientists used data from over 18,000 patients to identify at least 24 genetic risk factors involved in Parkinson’s disease, including the six newly reported ones. The investigators used a large volume of data from existing genome-wide association studies (GWAS) to identify these potential genetic risk variants, which increase the chances that a person may develop Parkinson’s disease. The results suggest that persons with more genetic variants may have a three times greater risk for developing the disorder in some cases.

Parkinson’s disease is a degenerative disorder that causes movement problems, such as trembling of the limbs, stiffness of limbs and trunk, slowed movements, and problems with posture. The disease progresses to a point where patients may be unable to perform simple tasks such as walking or talking. Millions of patients globally suffer from Parkinson's disease.

The exact cause of Parkinson's disease is not known yet. However, it is reported that about one-fifth of patients with Parkinson's disease have at least one relative who shows signs of the disease, indicating a definite genetic link. Nine genes have already been shown to cause rare forms of Parkinson’s disease, yet scientists continue to investigate whether other genetic risk factors are involved to provide a complete genetic picture of the disorder. Recently, other researchers at the University of California-Los Angeles, reported the discovery of another gene involved in Parkinson's called MUL1, which is detailed in Medical News Today. 

“Unraveling 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, Ph.D., a scientist at the NIH’s National Institute on Aging (NIA) and senior author of the study.

                                                                                                
Singleton and other scientists confirmed the results of their study in another sample of subjects, including 5,353 patients and 5,551 controls, using a gene chip called NeuroX. The NeuroX contains the codes of about 24,000 common genetic variants which are likely associated with various neurodegenerative disorders. By comparing the genetic regions of the patients and control subjects to sequences on NeuroX, researchers confirmed that 24 variants represent genetic risk factors for Parkinson’s disease.

"The replication phase of the study demonstrates the utility of the NeuroX chip for unlocking the secrets of neurodegenerative disorders," said Margaret Sutherland, a program director at the National Institute of Neurological Disorders and Stroke. "The power of these high tech, data-driven genomic methods allows scientists to find the needle in the haystack that may ultimately lead to new treatments."

The newly identified genetic risk factors may be involved with Gaucher’s disease, regulating inflammation and the nerve cell chemical messenger dopamine as well as the protein, alpha-synuclein which is implicated in Parkinson's disease. The exact roles of the variants identified in this study will need to be investigated further.