If I have Parkinson's disease (PD) 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.
What if my genetic test is positive for a Parkinson's gene?
Scientists have identified several genetic 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, PARK7, SNCA, LRRK2, parkin and PINK1.
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.
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. Discuss your reasons for being tested and the impact it may have on you and your family. Genetic testing helps estimate the risk of developing Parkinson's, but is not a diagnosis and cannot provide your probability for 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. They can shed light on gene-related issues, while providing emotional support.
There are commercial companies that offer genetic testing for Parkinson's disease. However, if you suspect you or a loved one has Parkinson's, consult with a neurologist and a genetic specialist before proceeding with genetic testing. Call the Parkinson's Foundation Helpline 1-800-4PD-INFO (473-4636) to find a genetic counselor.
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 the Genetics Initiative 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, PARK7, SNCA, LRRK2, parkin and PINK1. At-home tests only look for changes in LRRK2 (G2019S) and GBA (N370S) and do not map the entire gene to look for other mutations, which is a major goal of the Genetics Initiative.
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 development of new treatments. The Parkinson's Foundation Genetics Initiative 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.