We do not know exactly what causes Parkinson's disease (PD), but scientists believe that a combination of genetic and environmental factors are the cause. The extent to which each factor is involved varies from person to person. Researchers do not know why some people develop Parkinson's and others do not.
Genetics cause about 10% to 15% of all Parkinson's. In some families, changes (or mutations) in certain genes are inherited or passed down from generation to generation. A handful of ethnic groups, like the Ashkenazi Jews and North African Arab Berbers, more commonly carry genes linked to PD and researchers are still trying to understand why.
Regardless of how a person gets Parkinson's — through genetics or environment or a combination of both — every person with PD experiences a loss of dopamine in the brain, along with symptoms and a progression of their disease that is unique to them.
Enroll in Our Genetics Study Now
Understanding the connection between Parkinson's and genetics can help us understand how the disease develops and ultimately how it can be treated or cured. This is why studies like the Parkinson's Foundation PD GENEration study that is linking genetics to Parkinson's are essential.
Over the years, scientists have studied DNA from people with Parkinson's, comparing their genes. They discovered dozens of gene mutations linked to Parkinson's. These genes are now being researched and studied for what role they play in Parkinson's.
Even when someone has a gene mutation associated with Parkinson's, the likelihood of developing the disease is low. This is because researchers are only beginning to understand the role genes play in Parkinson's — like if certain genes cause Parkinson's and how other genes may protect some people from developing it.
Right now, we know that genetics, environmental influences and lifestyle choices collectively determine if someone will develop Parkinson's.
What If I Carry the Gene?
There are ongoing clinical trials testing therapies to treat people who have Parkinson's and carry certain gene mutations. Proving that it can be important to know which gene mutation you carry. Consult with your doctor when considering a genetic test to determine if you are eligible to participate in gene-based clinical trials.
The Parkinson’s Foundation study, PD GENEration: Mapping the Future of Parkinson’s Disease, is the first national study to offer genetic testing and counseling at no cost for those with a confirmed Parkinson’s diagnosis. Learn more and enroll.
If I have Parkinson's will my child get it too? Will I inherit Parkinson's if my parent or grandparent has it?
Most people with Parkinson's (about 90%) have no known genetic link. Their children will likely never develop Parkinson's. There are some known genetic variations that increase the risk of getting Parkinson's, but most people with these variations do not get Parkinson's. Like many other diseases, Parkinson's is a result of a complex interaction between genes and environmental factors.
In a small number of people (up to 10%), Parkinson's is inherited and can affect multiple family members. Their children may have a higher risk of developing Parkinson's. However, there is no guarantee they will develop PD.
Should I take an at-home genetics test to see if I will get Parkinson's?
Genetic tests are not a substitute for a diagnosis. Always consult with a genetic counselor before and after taking a genetic test. Most at-home genetic tests check for a limited number of genetic variants and mutations linked to PD and can be misleading. It is possible that those who test negative may still develop Parkinson's, as other PD-associated genes have yet to be discovered.
What if I take a genetic test and learn I carry a Parkinson's gene?
Scientists have identified gene changes (known as mutations) that can increase the risk of developing Parkinson's. If someone tests positive for a mutation in a Parkinson's gene, it does not necessarily mean they will develop PD. Some people who have mutations in the genes associated with Parkinson's (LRRK2 and GBA) never develop PD.
A person may inherit a hereditary genetic mutation that increases their risk for Parkinson's; however, they may also inherit other genes, be exposed to environmental factors or have lifestyle choices that offset the risk. Genetic testing is currently available for the following genes related to Parkinson's: GBA, LRRK2, PRKN, SNCA, PINK1, PARK7 and VPS35.
Am I more likely to get Parkinson's because of my genes or environment?
Parkinson's in most people is thought to be a complex interaction between environmental factors and genetics. A person who is genetically pre-disposed to Parkinson's might be exposed to certain environmental factors (pesticides and herbicides) and have lifestyle choices (exercise, smoking, caffeine) that can influence the risk for developing Parkinson's. Typically, in most people with Parkinson's, it is difficult to unravel the environmental influences from the genetic components.
However, in rare instances when multiple family members have Parkinson's, certain gene mutations are inherited that are more likely to contribute to developing PD.
Should I see a genetic counselor if a family member has Parkinson's?
If Parkinson's runs in your family and you want to get genetically tested, consult with a genetic counselor first. Genetic testing helps estimate the risk of developing Parkinson's, but is not a diagnosis and cannot provide your probability of developing the disease. A genetic counselor is a specialist on a healthcare team who provides risk assessments and education about genetics and how to read test results. Call the Parkinson's Foundation Helpline 1-800-4PD-INFO (473-4636) to find a genetic counselor.
There are commercial companies that offer genetic testing for Parkinson's. Additionally, the Parkinson’s Foundation PD GENEration study offers genetic testing and counseling to all participants.
What can I do with my genetic test results?
Always talk to your doctor about genetic testing in Parkinson's and speak to a genetic counselor before and after taking the test. Knowing your genetic status can provide a sense of empowerment and control and may lead to better treatment and care.
Identifying your genetic mutations can help you determine if you are eligible to enroll in certain clinical trials. Several ongoing clinical trials are already testing treatments for people who carry certain PD gene mutations in LRRK2 and GBA.
For people with Parkinson's, genetic tests are either not available or not affordable, and not covered by health insurance or offered with genetic counseling. Studies like PD GENEration are underway and offer free genetic testing for the GBA and LRRK2 genes and genetic counseling.
Currently, genetic testing is available through your doctor for the following genes: GBA, LRRK2, PRKN, SNCA, PINK1, PARK7 and VPS35. At-home tests only look for changes in LRRK2 and GBA and do not map the entire gene to look for other mutations, which is a major goal of PD GENEration.
What research is being done on genetics and Parkinson's?
Genetics can be a powerful tool used to help us understand what is responsible for slowing or stopping the progression of Parkinson's, ultimately helping us improve care and speed the development of new treatments. The Parkinson's Foundation PD GENEration study is working to accelerate PD research and care as we track the genetic makeup of 15,000 people with Parkinson's in the U.S.
Enroll now in our genetics study.
The Parkinson’s Foundation genetic study, PD GENEration: Mapping the Future of Parkinson’s Disease, provides genetic testing and genetic counseling at no cost to people with Parkinson’s.