Is Parkinson’s Disease Hereditary? Genetics and Causes

Parkinson’s disease is a genetic disease, but it’s rarely a hereditary disease. The condition can be caused by genetic changes that are inherited, or passed, from parent to child. Most genetic changes are random mutations that people don’t inherit from one or both parents.

Parkinson’s disease is a brain disorder that causes nerve cells to die and progressively worsens over time. The exact cause of Parkinson’s disease is unknown. Research has shown that a combination of genetic and environmental factors likely play a role.

About 10% to 15% of people who develop Parkinson’s disease have genetic changes related to the condition. This component remains poorly understood, but researchers have identified several genes linked to the condition. Read on to learn how genetic changes are involved in Parkinson’s disease.

There are some genetic markers for Parkinson’s disease. These markers don’t guarantee that a person will develop the disease. A genetic mutation is just one of several risk factors for Parkinson’s disease. Parkinson’s disease can be inherited, or passed from parent to child, but it’s not common. As many as 15% of people with Parkinson’s disease have a family history of the condition.

One of the genetic factors in play is called “causal,” meaning the gene itself can cause the disease. An example of a causal link to Parkinson’s disease is the SNCA gene. Researchers know of at least 30 mutations in this particular gene that cause Parkinson’s disease, especially in people younger than 50.

The SNCA gene tells the body how to make a protein called alpha-synuclein. The body may produce too much of this protein or have an incorrect shape when the SNCA gene has a mutation. Either of these problems can lead to a cluster of proteins called Lewy bodies. Lewy bodies disrupt normal brain functioning and are associated with Parkinson’s disease and other conditions.

Not all genetic changes cause Parkinson’s disease. “Associated” genetic factors increase a person’s odds of the condition but aren’t directly responsible for it. You’re susceptible, but you need something else present to develop the disease. This could be other genes or an environmental factor.

Autosomal Dominant

You get two copies of each gene, one from each parent. Autosomal dominant inheritance means that one inherited copy of a faulty gene can cause Parkinson’s disease. This type of inheritance gives you a 50% chance of developing the condition.

Research has linked autosomal dominant genes to Parkinson’s disease, including:

• LRRK2 (PARK8)
• PARK3
• SNCA (PARK1)
• UCHL1 (PARK5)

Autosomal Recessive

Autosomal recessive inheritance means both parents carry a copy of the faulty gene. You’ll have a 25% chance of inheriting the faulty gene and an increased risk of Parkinson’s disease.

Autosomal recessive genes linked to Parkinson’s disease include:

• DJ-1
• PARK2
• PARK7
• PINK1 (PARK6)
• PRKN

Just because you have a mutation on a specific gene or a relative with Parkinson’s disease doesn’t mean you will develop the disease. A combination of factors, in addition to genetics, contribute to the disease.

Other risk factors that increase the likelihood of Parkinson’s disease include:

• Age (i.e., older than 60)
• Being assigned male at birth
• Exposure to herbicides or pesticides
• Previous brain or head injury

You can’t completely prevent Parkinson’s disease. There are still some steps you can take to lower your risk, including:

• Avoid exposure to toxins, including herbicides or pesticides
• Keep track of side effects like tremors if you take certain medications
• Stay physically active, which may slow the onset and progression of Parkinson’s disease
• Wear protective headgear if there’s a risk of brain or head injury, such as if you play contact sports

Contact a healthcare provider if you develop early Parkinson’s disease symptoms like:

• Changes in behavior
• Constipation
• Depression
• Difficulty balancing, talking, or walking
• Muscle stiffness
• Shaking
• Slow movements
• Urinary problems

You may consider genetic testing for markers for Parkinson’s disease if you have a family history of the disease. At-home genetic tests can determine if you have specific genetic markers. Keep in mind that most people with genes linked to Parkinson’s never get the disease. You may have unnecessary stress and worry if your results reveal one of these genetic factors.

Various factors, including genetic and environmental ones, contribute to Parkinson’s disease. Most people with genes associated with Parkinson’s disease never develop the disease. It can be helpful to be aware of the genetic component in some situations, but you don’t need to panic if you have one of those mutations.

Keep in mind that research is ongoing. Researchers still don’t know the exact cause of Parkinson’s disease. There is still much more to learn, even with all the available information.