Researchers Identify Gene Mutations Underlying Risk for Most Common Form of Parkinson's Disease
Researchers have found that two genes containing mutations known to cause rare familial forms of Parkinsonís disease are also associated with the more common form of the disease where there is no family history.
Balintfy: Collaborating scientists in the United States and Europe pooled nearly 14,000 DNA samples and data to confirm that mutations in specific genes, and associated proteins — both present in the general population — are risk factors for Parkinson's disease. Dr. Andrew Singleton, chief of the Laboratory of Neurogenetics at the National Institute on Aging, explains, scientists have already identified five genes whose rare mutations cause the disease.
Dr. Singleton: What we found with this latest study, is that two, and possibly three of those genes, also contained common variants that you or I have a very high chance of carrying, theyíre present in 20 or 30 percent of the population. So these common variants increase our risk.
Balintfy: But Dr. Singleton is quick to add that these genetic mutations donít cause Parkinsonís disease. Rather these variations add to the risk by a small amount, only about 20-30 percent.
Dr. Singleton: A good way to conceptualize this is that if you were to take a hundred people from the general population on average, about one of those would get Parkinsonís Disease. And if you were to take a hundred people from the general population, who all carried the risk variants that we found, about one or about two people would, from that population, would get disease. So, itís a fairly moderate increase in risk for disease.
Balintfy: Parkinson's disease is a progressive neurologic disorder caused by the degeneration of nerve cells in the portion of the brain that controls movement. The likelihood of developing the disorder increases with age and involves a combination of environmental risk factors and genetic susceptibility. Dr. Singleton says there are about one million people in North America affected with Parkinsonís disease.
Dr. Singleton: But of course, given that the population is aging, weíre all aging a bit more successfully and everybodyís living a little bit longer, there will be more people affected with Parkinsonís Disease over the next 10 or 20 years.
Balintfy: Because of the potential increase in cases, Dr. Singleton says these findings, presented in a recent online issue of Nature Genetics, are important to help understand the disease.
Dr. Singleton: So, I donít see immediate use for this in identifying people who are going to get disease or providing risk profiles for people, I think we will get there, but thatís a ways off yet. What it really tells us is that the genes that weíve identified are intimately involved in the process that leads to Parkinsonís disease, so it really gives us an in to understanding what are the molecular events that lead to disease, and of course once we know that, weíre one step closer to trying to find a point in that process to halt the disease or to reverse the disease process.
Balintfy: The finding came in the largest genome-wide association study reported to date involving Parkinson's disease. Genome-wide association studies look in the DNA of individuals in a specific population for common genetic associations with a disease. To date, such studies have been done on relatively small numbers of samples and have not been able to identify genetic variations of smaller effect in Parkinson's disease. But now, genome-wide association studies in very large sample sets are able to identify these elusive genetic variations. For more information on this study, visit www.nia.nih.gov. This is Joe Balintfy, National Institutes of Health, Bethesda, Maryland.
About This Audio Report
Reporter: Joe Balintfy
Sound Bite: Dr. Andrew Singleton
Topic: Parkinsonís, Parkinsonís disease, Parkinsonís gene, genes, genetic mutation, genetic variation, genetic risk, risk factors, genome, GWAS