Genetic Testing and Counselling

Genetics and Parkinson’s

Genetic mutations, also known as variants, can occur within an individual, or be passed down through familial genetic history (Parkinson’s Foundation, n.d.). Some of these mutations are associated with an increased risk of Parkinson’s disease (PD). However, most people with Parkinson’s do not have family history of the disease – in fact, only 15% of cases show a heritable link (Johns Hopkins Medicine, n.d.).

Certain genes, when mutated, create proteins that do not work properly, or do not work at all (Parkinson’s Foundation, n.d.). The Parkinson’s Foundation and the Michael J. Fox Foundation for Parkinson’s Research provide some examples of specific proteins and their effects on Parkinson’s, which include:

SNCA: This gene, when mutated, causes clumps of itself to form in the brain of people with PD. Mutations in SNCA can lead to abnormal accumulation of alpha-synuclein in the brain, forming clumps known as Lewy bodies, which are found in most people who have PD. This gene was the first Parkinson’s-related gene to be identified in 1997 (Michael J. Fox Foundation, n.d.). SNCA also produces alpha-synuclein, the protein most people associate with Parkinson’s disease (Johns Hopkins Medicine, n.d.).
GBA: Mutations in this gene reduce the activity of glucocerebrosidase (GCase), an enzyme that helps brain cells break down certain fats and keep their internal clean-up system working. When GCase doesn’t work properly, fats and unwanted proteins, especially alpha-synuclein, can build up inside cells and damage them. Because of this, GBA mutations are one of the most common genetic risk factors for Parkinson’s and are linked to earlier onset and faster progression of the disease (Smith & Schapira, 2022).
PRKN: This gene, when mutated, is the most common genetic cause of Young-Onset Parkinson’s Disease (YOPD), including a rare form that appears before age 20 and other early-onset cases, typically before age 40. These mutations often result in a faulty or missing protein called parkin, which normally helps cells get rid of unwanted proteins. Without working parkin, these proteins can build up, disrupting normal cell functions, including the release of dopamine. Over time, this damages or kills brain cells that produce dopamine (Medline Plus, n.d.).
PINK1: This gene, when mutated, is also found in cases of YOPD. Like PRKN, it affects dopamine production, and may also disrupt mitochondrial regulation (Parkinson’s Foundation, n.d.).
PARK7: This gene, when mutated, is a rare genetic cause of YOPD. It reduces the protective nature of an important cellular protein called DJ-1, leading to a reduction in dopamine neurons (Parkinson’s Foundation, n.d.).
VPS35: This gene, when mutated, is a rare genetic cause of late-onset PD. It is a moderately new discovery, found in 2011. Its mutation causes a breakdown in communication between brain proteins.
LRRK2: This gene, when mutated, affects certain ethnic groups more prevalently than others. People of Ashkenazi Jewish and North African Berber descent who have PD exhibit a much larger percentage of a mutated LRRK2 gene than other ethnic groups. Genetic mutations can make LRRK2 too active, which changes brain cells and interferes with communication between dopamine-producing neurons and cells in the striatum, a brain region involved in movement, motivation, and decision-making. This can lead to the motor and non-motor symptoms seen in Parkinson’s disease (Jaimon et al., 2025).

What is PD-related Genetic Testing?

Genetic testing aims to identify genetic variants associated with an increased risk of Parkinson’s disease in an individual’s DNA. Specifically, genetic tests look for mutated cellular proteins that can influence the chance of someone developing PD.

What is PD-related Genetic Counselling?

Genetic counselling for PD is a crucial part of genetic care. Before genetic testing, trained genetic counsellors provide individuals and families with information about genetic risks and disorders, helping them decide whether testing is appropriate (Canadian Association of Genetic Counsellors, n.d.).

If genetic testing is conducted, counsellors interpret data to provide their patients with next steps for diagnoses, treatment, and prevention. They also provide emotional support counselling, advocate for their patients, and refer them to other appropriate medical services (Canadian Association of Genetic Counsellors, n.d.).

If you are considering genetic testing, the services of a genetic counsellor are necessary for understanding any potential genetic disorders. Genetic testing alone cannot diagnose Parkinson’s and is primarily used to assess risk, guide counselling, and inform research or eligibility for clinical trials (Michael J. Fox Foundation, n.d.).

Does Genetic Testing Guarantee a Diagnosis of PD?

While genetic testing focuses on specific gene mutations that are correlated with Parkinson’s, this does not mean that having those mutations guarantees a diagnosis of PD. Many people with PD do not have a genetic mutation linked to Parkinson’s, and many people without PD have a genetic mutation linked to the disease (Michael J. Fox Foundation, n.d.).

Having a genetic mutation linked to PD does increase the risk of developing the disease, in conjunction with other risk factors, such as lifestyle choices, environmental factors, and exposure to potential PD-causing chemicals. Different genetic mutations carry different risks of developing PD. Some mutations have higher risks than others.

Where Can You Find Genetic Testing/Counselling in BC?

Genetic counsellors located in BC will be able to refer patients to genetic testing services. Genetic counselling through Provincial Health Services can be found through the Provincial Medical Genetics Program at the BC Women’s Hospital + Health Centre, located at Door #77 at 4500 Oak St, Vancouver, BC, V6H 3N1. This clinic offers in-person services by appointment, and also over the phone and through video conference. Outreach clinics are available in Kelowna and Prince George.

If you live or reside on Vancouver Island, the Vancouver Island Health Authority Medical Genetics offers genetic testing and counselling. Appointments are offered in-person at the Victoria General Hospital, located at 1 Hospital Way, Victoria, BC, V8Z 6R5, or the Nanaimo Regional General Hospital, located at 1200 Dufferin Crescent, Nanaimo, BC, V9S 2B7.

Additionally, the Parkinson’s Foundation offers a free online source for genetic testing and counselling through their program, PD GENEration. This service is available globally, with Canadian participants being able to enroll here. Note: This service is only available to adults who already have PD.

Referrals are needed to access the services from the Provincial Medical Genetics Program or the Vancouver Island Health Authority Medical Genetics Program.

What Do You Need to Get a Referral for Genetic Testing/Counselling?

The Provincial Medical Genetics Program and the Island Health Medical Genetics Program provide referral forms to bring to your doctor on their websites.

Find the Provincial Medical Genetics Program referral documents here.

Find the Island Health Genetics Program referral documents here.

Genetic testing and counselling is not a conclusive medical process to determine if you currently have or will develop PD. However, this service can provide you and your family with information about genetic risk factors that may increase the chances of developing PD. There are many different types of genetic mutations that may increase the chance of Parkinson’s, and the help of a genetic counsellor is required to understand the results of genetic testing. Consult the sources of information provided in this help sheet to help decide whether genetic testing/counselling is right for you, and make sure to speak with your healthcare team if you have any questions.

Sources

The Genetic Link to Parkinson's Disease. Johns Hopkins Medicine. (n.d.). https://www.hopkinsmedicine.org/health/conditions-and-diseases/parkinsons-disease/the-genetic-link-to-parkinsons-disease

Genetic Testing & Counselling. Parkinson’s Foundation. (n.d.). https://www.parkinson.org/understanding-parkinsons/causes/genetics/testing-counseling

Current findings from PD Generation. Parkinson’s Foundation. (n.d.). https://www.parkinson.org/advancing-research/our-research/pdgeneration/genetics-behind-pd#variant_data

Parkinson’s genetics. The Michael J. Fox Foundation for Parkinson’s Research | Parkinson’s Disease. (n.d.). https://www.michaeljfox.org/news/parkinsons-genetics

What to Know About Genetic Testing. The Michael J. Fox Foundation for Parkinson’s Research | Parkinson’s Disease. (n.d.). https://www.michaeljfox.org/what-know-about-genetic-testing

What is A Genetic Counsellor?. Canadian Association of Genetic Counsellors. (n.d.). https://www.cagc-accg.ca/?page=353

Child and Adult Assessment. Provincial Medical Genetics Program. (n.d.). https://www.bcwomens.ca/our-services/medical-genetics/child-adult-assessment

Medical Genetics Services. Vancouver Island Health Authority Genetics Program. (n.d.). https://www.islandhealth.ca/our-services/medical-genetics-services/medical-genetics-services

Understanding Genetics. Parkinson’s Foundation. (n.d.). https://www.parkinson.org/understanding-parkinsons/causes/genetics/understanding-genetics

Smith, L., & Schapira, A. H. V. (2022). GBA variants and Parkinson disease: Mechanisms and treatments. Cells, 11(8), 1261. https://doi.org/10.3390/cells11081261

PRKN gene. MedlinePlus. (n.d.). https://medlineplus.gov/genetics/gene/prkn

Jaimon, E., Lin, Y.-E., Tonelli, F., Antico, O., Alessi, D. R., & Pfeffer, S. R. (2025). Restoration of striatal neuroprotective pathways by kinase inhibitor treatment of Parkinson’s disease–linked LRRK2-mutant mice. Science Signaling, 18(893). https://doi.org/10.1126/scisignal.ads5761

Last updated: January 22, 2026

Search