When Michael’s father was diagnosed with Parkinson’s disease at age 58, the question that kept him awake at night wasn’t just about his father’s prognosis—it was about his own future.
Like many adult children of people with Parkinson’s, Michael wondered whether he carried the genetic variants that might put him at risk. Should he get tested? Would knowing help or hurt? These are questions that thousands of families grapple with each year.
Genetic testing for Parkinson’s disease has become increasingly accessible, but the decision to pursue it is far from simple. Unlike testing for some genetic conditions where the results provide clear, actionable information, Parkinson’s genetics exists in a more complex landscape.
Understanding what genetic testing can and cannot tell you is essential for making an informed decision that’s right for your family.
Understanding the Genetic Landscape of Parkinson’s
Parkinson’s disease is predominantly what scientists call a “sporadic” condition, meaning it occurs without a clear hereditary pattern in about 90% of cases.
However, genetics does play a role, though that role varies considerably from person to person.
Approximately 10-15% of people with Parkinson’s have a family history of the disease. Within this group, only a small percentage—roughly 5-10% of all Parkinson’s cases—can be attributed to specific genetic mutations that are passed down through families.
These are known as “monogenic” forms of Parkinson’s, where a single gene mutation causes the disease.
The most well-studied genes associated with Parkinson’s include LRRK2, PARK7, PINK1, PRKN (also known as PARK2), and SNCA. Some of these genes, when mutated, virtually guarantee that someone will develop Parkinson’s—these are called “penetrant” genes.
Others increase risk but don’t determine destiny—these are “susceptibility” genes.
The LRRK2 gene mutation, for instance, is the most common known genetic cause of Parkinson’s disease. However, even carrying the most common LRRK2 mutation (G2019S) doesn’t mean you’ll definitely develop Parkinson’s.
The penetrance—the likelihood that someone with the mutation will develop the disease—varies, with estimates ranging from 30% to 70% by age 80, depending on which study you consult.
Then there’s the GBA gene, which presents an even more complex picture. Variants in GBA don’t cause Parkinson’s directly but significantly increase risk—making them perhaps the most common genetic risk factor for the disease.
Yet most people with GBA variants never develop Parkinson’s at all.
This complexity is crucial to understand before pursuing genetic testing. Unlike testing for conditions such as Huntington’s disease, where a positive result means you will almost certainly develop the condition, Parkinson’s genetic testing often reveals probabilities rather than certainties.
Who Should Consider Genetic Testing?
The decision to pursue genetic testing is highly personal, but certain circumstances make it particularly worth considering.
Early-onset Parkinson’s disease is one of the strongest indicators for genetic testing. When someone develops Parkinson’s symptoms before age 50—and especially before age 40—the likelihood of a genetic cause increases substantially.
In these cases, identifying a genetic mutation can sometimes influence treatment decisions and provide valuable information for other family members.
Multiple affected family members is another strong reason to consider testing. If you have two or more blood relatives with Parkinson’s disease, particularly if they’re in the same generation or in parent-child relationships, genetic factors are more likely to be at play.
This is especially true if the disease appeared at relatively young ages in these family members.
Ashkenazi Jewish ancestry deserves special mention. Both LRRK2 and GBA mutations are more common in people of Ashkenazi Jewish descent. If you have this heritage and a family history of Parkinson’s, genetic testing may be particularly informative.
Reproductive planning is a consideration for some families. If you or your partner carries a genetic mutation for Parkinson’s and you’re planning to have children, you may want to know about potential genetic risks.
While most Parkinson’s genes don’t follow simple inheritance patterns, some do, and this information might influence reproductive decisions.
The Testing Process: What to Expect
Genetic testing for Parkinson’s typically begins with a visit to a genetic counselor—a healthcare professional specially trained in genetics and counseling. This initial consultation is perhaps the most important step in the entire process.
During this session, the genetic counselor will construct your family medical history, often going back several generations.
They’ll ask detailed questions about who in your family had Parkinson’s, at what age symptoms appeared, and what other medical conditions run in your family. This information helps determine which genetic tests, if any, might be most informative for you.
The counselor will also explain what different test results might mean, discuss the psychological implications of testing, and help you think through how you might use the information.
This pre-test counseling is crucial because it helps ensure you’re making an informed decision and prepares you for whatever results you might receive.
If you decide to proceed with testing, the actual process is straightforward—usually just a blood sample or cheek swab. The sample is sent to a specialized laboratory where technicians analyze specific genes associated with Parkinson’s disease.
Results typically take several weeks to several months, depending on the complexity of the testing. When results are ready, you’ll meet again with the genetic counselor to interpret them and discuss their implications.
Interpreting Results: It’s Rarely Black and White
Genetic test results for Parkinson’s generally fall into three categories, though the implications of each can be nuanced.
A positive result means a mutation was found in one of the genes associated with Parkinson’s disease.
However, as discussed earlier, this doesn’t necessarily mean you will develop Parkinson’s. The significance depends heavily on which gene is affected and which specific mutation was found.
Your genetic counselor will explain what is known about your particular variant, including penetrance rates and typical age of onset.
A negative result means no mutations were found in the genes that were tested. This can be reassuring, but it’s important to understand its limitations.
A negative result doesn’t mean you have no genetic risk for Parkinson’s—it simply means you don’t have mutations in the specific genes that were analyzed.
Remember, scientists don’t yet know all the genetic factors involved in Parkinson’s disease, and the vast majority of people with Parkinson’s don’t have identifiable genetic mutations.
A variant of uncertain significance (VUS) is perhaps the most challenging result. This means the laboratory found a genetic change, but scientists don’t yet know whether this change affects disease risk.
As research progresses, some VUS results are eventually reclassified as either pathogenic (disease-causing) or benign (harmless), but living with uncertainty in the meantime can be difficult.
The Case for Testing: Potential Benefits
For the right person in the right circumstances, genetic testing can offer several meaningful benefits.
Knowledge and certainty matter to many people. Even if the information doesn’t change immediate medical management, knowing your genetic status can help reduce uncertainty and allow for more informed life planning.
Some people find this empowering, preferring to confront potential risks directly rather than living with ambiguity.
Participation in research is another significant benefit. Individuals with identified genetic mutations are often eligible for clinical trials and research studies that might not be available to others.
As scientists work toward disease-modifying treatments for Parkinson’s, many of these studies specifically target people with certain genetic forms of the disease.
Being able to participate in cutting-edge research can be meaningful both personally and for the broader Parkinson’s community.
Treatment implications are emerging for some genetic forms of Parkinson’s. While Parkinson’s treatment has traditionally been the same regardless of genetic status, this is beginning to change.
For example, people with certain genetic mutations might respond differently to specific medications, and targeted therapies are in development for some genetic forms of the disease.
Family planning and information can be valuable for some families. If you test positive for a genetic mutation, this information can be shared with siblings, children, and other relatives who might also want to know their status. This can facilitate informed decision-making across the family.
The Case Against Testing: Potential Drawbacks
Despite these potential benefits, genetic testing isn’t right for everyone, and there are legitimate reasons to decline testing.
Psychological impact is a primary concern. Learning you carry a genetic mutation associated with Parkinson’s can cause anxiety, depression, and worry about the future—even if you never develop symptoms.
Some people find this knowledge burdensome rather than empowering. If you’re someone who tends toward anxiety or already struggles with health-related worry, the psychological costs might outweigh the benefits.
Limited actionability is another consideration. Currently, there are no proven preventive treatments for Parkinson’s disease, even if you know you carry a genetic mutation.
Unlike genetic testing for conditions where early detection enables preventive interventions, Parkinson’s testing often doesn’t change what you can do medically. You can’t reverse the genetic risk, and there’s no definitive way to prevent the disease.
Genetic discrimination concerns worry many people, though legal protections exist. The Genetic Information Nondiscrimination Act (GINA) protects Americans from genetic discrimination by health insurers and employers.
However, GINA doesn’t cover life insurance, disability insurance, or long-term care insurance. Some people worry that genetic test results could affect their ability to obtain these types of coverage, though insurers cannot access medical information without your consent.
Family dynamics can become complicated when genetic information enters the picture. If you test positive for a mutation, it means your siblings have a 50% chance of carrying the same mutation (for most Parkinson’s genes). Some relatives may want to know this information; others may not.
Navigating these family conversations can be stressful and can sometimes create tension or guilt.
False reassurance or unnecessary worry can result from misinterpreting test results. A negative result doesn’t mean you won’t develop Parkinson’s, and a positive result doesn’t mean you will.
If these nuances aren’t properly understood, testing can lead to either false security or unnecessary anxiety.
Alternative Approaches: What If You’re Not Ready to Test?
If you’re uncertain about genetic testing, there are alternative approaches to consider.
Vigilant monitoring without testing is one option. You can work with your healthcare provider to establish a baseline of your neurological health and monitor for any early signs of Parkinson’s through regular check-ups. This approach allows you to stay informed about your health without seeking genetic information.
Focusing on modifiable risk factors is something everyone can do, regardless of genetic status. While you can’t change your genes, research suggests that certain lifestyle factors may influence Parkinson’s risk.
Regular exercise, maintaining cardiovascular health, eating a diet rich in antioxidants, avoiding head injuries, and limiting exposure to certain pesticides and toxins may all play a role in reducing risk or delaying onset.
Delayed testing is always an option. You don’t have to decide about genetic testing immediately. Some people prefer to wait until they’re older, until their life circumstances change, or until more is known about the genetic basis of Parkinson’s and potential treatments.
The option for testing will likely still be available in the future, potentially with even more informative results as science advances.
Making Your Decision: Questions to Consider
As you contemplate genetic testing, consider asking yourself these questions:
- How would I use the information from genetic testing? Would it change my medical care, life planning, or other decisions?
- How do I typically cope with health-related uncertainty? Do I prefer to have information, even if it’s worrying, or am I more comfortable not knowing?
- What are my primary motivations for testing? Am I seeking knowledge for its own sake, hoping to participate in research, planning for the future, or hoping to protect family members?
- How would a positive result affect my mental health and quality of life? Could I manage the psychological impact?
- Do I have adequate support systems in place? Do I have family, friends, or mental health professionals who could help me process the results?
- What are my concerns about privacy and discrimination? Have I researched the legal protections available to me?
- How might this information affect my family relationships? Are other family members prepared to receive information about their own potential risks?
The Importance of Genetic Counseling
Regardless of whether you ultimately decide to pursue testing, meeting with a genetic counselor is invaluable.
These professionals can provide personalized guidance based on your specific family history, help you understand the nuances of Parkinson’s genetics, and support you through the decision-making process.
Genetic counselors can also connect you with resources, including support groups for people with genetic forms of Parkinson’s or for those considering testing.
They can facilitate family conversations about genetic risk and help you develop a plan for how to use genetic information if you do test positive.
Many people find that the counseling process itself, separate from any testing, provides clarity and peace of mind.
Looking Ahead: The Future of Genetic Testing for Parkinson’s
The field of Parkinson’s genetics is advancing rapidly. Researchers are identifying new genes associated with the disease, developing better understanding of how genes interact with environmental factors, and working toward targeted therapies for specific genetic forms of Parkinson’s.
In the future, genetic testing may become more informative and more actionable.
Scientists are working on treatments that could potentially delay or prevent Parkinson’s in people with high genetic risk. As these treatments develop, the value of genetic testing will likely increase.
For now, the decision to pursue genetic testing remains deeply personal, requiring careful consideration of both scientific facts and individual values, circumstances, and emotional needs.
Conclusion
The question “Should I get genetic testing for Parkinson’s?” has no universal answer. For some people—particularly those with early-onset disease, strong family histories, or who want to participate in research—testing can provide valuable information and opportunities. For others, the psychological burden and limited actionability make testing less appealing.
What’s most important is making an informed decision that aligns with your values, circumstances, and goals.
Genetic testing is a tool, and like any tool, its value depends on how and when it’s used.
If you’re considering genetic testing, start with a genetic counselor who can provide personalized guidance.
Take time to reflect on how you would use the information and how it might affect your life. Talk with your family, healthcare providers, and anyone else who might be affected by your decision.
Remember that choosing not to test is just as valid as choosing to test. Either way, focus on what you can control: living a healthy lifestyle, staying connected with loved ones, supporting Parkinson’s research, and making the most of each day—regardless of what your genes might hold.
