Did you know your genes can affect your risk of stroke? The good news is that even if stroke runs in your family, it doesn’t mean you’re destined to have one. Here’s how genetics and lifestyle impact your risk, and what steps you can take to protect your brain health.
What is a stroke?
A stroke is defined as the sudden loss of a brain function. The exact function lost depends on which part of your brain is affected:
- Damage to the motor area of the frontal lobe may cause paralysis.
- Damage to the visual area of the occipital lobe can cause partial vision loss.
In other words, a stroke causes a focal deficit — a problem with a specific brain function — rather than the loss of all neurological functions.
When someone has a sudden, localized neurological deficit, a physical exam can help identify the problem and locate which part of the brain is affected. Brain imaging, such as an MRI, can then confirm whether a stroke has indeed occurred and what type of stroke it is:
- Hemorrhagic stroke: occurs when a brain artery ruptures and causes bleeding.
- Ischemic stroke: the most common type, caused when a blood clot blocks an artery and cuts off oxygen and glucose to part of the brain, leading to brain tissue damage (a cerebral infarction).
What role do genes play in stroke?
Like many diseases, your risk of having a stroke depends on your unique mix of genetic makeup and lifestyle habits, such as smoking or eating lots of salty and fatty foods.
For most people, genetics plays a complex role. Many small genetic changes, each with only a tiny effect, can add up to raise your risk of stroke. This is called polygenic risk. Whether a stroke occurs depends on how these genetic variants interact with lifestyle and environmental factors.
In a small proportion of cases, a single gene mutation (called a monogenic disease) is enough to significantly increase stroke risk. Examples include CADASIL, Fabry disease, and certain mutations in the COL4A1 and COL4A2 collagen genes.
Signs that stroke risk may be linked to a strong genetic predisposition include:
- Having a stroke at a young age
- A family history of early strokes
- Certain ethnic backgrounds (for example, sickle cell anemia)
How genes can influence stroke
Your genetics can affect your stroke risk and outcomes in several ways:
- Whether you develop risk factors for stroke (such as high blood pressure, diabetes, high cholesterol, or obesity).
- Whether those risk factors develop into causes of stroke (like atrial fibrillation, atherosclerosis, or cerebral amyloid angiopathy).
- How likely you are to bleed easily or develop blood clots (called a prothrombotic state).
- How well you respond to preventive treatments (like anticoagulants or blood pressure medications) and to emergency treatments during a stroke (like clot-busting drugs, called thrombolysis).
- How severe a stroke may be (for example, how well your brain can tolerate a temporary lack of oxygen and glucose).
- How well your brain can recover after a stroke (your brain’s plasticity—or ability to adapt).
- Whether you develop complications after a stroke (such as depression or cognitive decline).
Preventing a stroke: what you can do
Even if you are genetically predisposed, stroke can often be prevented. Stroke prevention has three main parts:
- Controlling stroke risk factors — such as high blood pressure, diabetes, high cholesterol, obesity, and smoking.
- Using the right medications — antithrombotic drugs are used to prevent clots in ischemic stroke, while they are avoided in hemorrhagic stroke to reduce bleeding risk.
- Treating the underlying causes of stroke — for example, surgery to restore blood flow in carotid artery atherosclerosis. New treatments are also becoming available for some single-gene diseases like Fabry disease, ADA2 deficiency, and sickle cell anemia.
Key Takeaway
Your genes affect your stroke risk, but they don’t decide your future. There are things you can start doing today to protect your brain health, even if stroke runs in your family. A good first step is to talk to your doctor.
