These days, we hear a lot about genetic research and breakthroughs. As scientists learn more about the human genome, everyday people like us benefit from the new knowledge gained and shared with the world.
But, advancements in understanding genetics can also be kind of scary.
What if you discover you’re at risk for a type of disease—like cancer or another illness?
Knowing you may be carrying the potential for an illness or disease can feel like you’re walking around with a ticking time bomb inside you. What if it gets triggered? What then?!
When it comes to dementia, many people are concerned. Is dementia hereditary? If my mother or father or great uncle Leo develops dementia, does that mean I will, too?
Coping with a close loved one with dementia is stressful enough in and of itself, without the added worry that you may be next.
Since you clicked on this article, you’re clearly interested in learning more about the genetic risk factors for dementia. And that’s great. Because knowledge is powerful.
It’s important to remember—even if you’re at risk for developing an issue or condition, the chances it’ll definitely happen are typically rare.
With conditions like dementia, educating yourself is crucial. That’s because a major way dementia is treated is by staying out ahead of the symptoms and changes it creates.
Let’s explore this answer more deeply, to give you the knowledge you need to understand the hereditary components of dementia.
Is Dementia Hereditary? What Does Science Have to Say?
If you’ve been holding your breath, waiting for a straight answer—breathe!
Because dementia is not believed to be directly caused by genes.
Dementia is a complex, multifactorial condition. While your genes may contribute to an increased risk for some types of dementia—they do not cause it directly.
Genetics is also complex. What science currently tells us is this: While having certain gene variants can potentially contribute to the development of dementia, this risk is highly dependent on additional environmental and social factors.
Even if you possess the gene variants that can lead to dementia, that doesn’t mean you’ll develop it. It only means your risk is increased. And remember—a risk isn’t a certainty.
In rare types of dementia, such as Huntington’s disease (HD), there is a strong, directly traceable genetic link.
But, here’s the thing—most people with a family history of Huntington’s disease know full well they have a history of this illness in their family.
In fact, many seek out genetic testing to gain even more clarity on their risks for developing this disease, as parents with HD have a 50% chance of passing the faulty gene responsible for this issue onto their children.
To examine dementia heredity more closely, let’s break it down by the primary dementia types, so you can learn the genetic risks that exist for each one (hint—most dementia types carry little to no risk of being passed down genetically).
We’ll kick things off by looking at the most common type of dementia, and the one about which people are most familiar.
Is Alzheimer’s Disease Hereditary?
If someone you love develops Alzheimer’s disease, it stands to reason you may want to know if you’re also at risk for this diagnosis. And, if so, what your risk is.
If you have an immediate family member with Alzheimer’s disease (meaning a parent or sibling), research does show an increased risk for developing this condition than if that were not the case. But let’s dive a little deeper into this risk.
Some studies have looked into the familial risk for Alzheimer’s by studying twins. What they’ve found is—even when one twin has Alzheimer’s, the other only has a 40-50% chance of developing it, too.
This tells us that genes aren’t the whole story.
Other factors play a larger role in whether or not a person will develop Alzheimer’s disease.
A very small percentage of Alzheimer’s disease cases are caused by what’s known as familial Alzheimer’s. This type of Alzheimer’s origin is very rare, and researchers are currently investigating the genetic basis for this specific type of Alzheimer’s.
If you’re concerned about your risks for developing Alzheimer’s disease, you can learn more about genetic testing to help determine your personal risks.
Because of the strong emotional component of learning your genetic risks, it’s recommended that you first pursue genetic counseling services, to help you navigate this process and understand your results.
Is Vascular Dementia Hereditary?
For the most part, vascular dementia is not considered to be hereditary. Because it’s closely related to stroke, the risks for vascular dementia are more closely related to risks for stroke than to any genetic factors.
And what are the major risk factors for stroke? High blood pressure, diabetes, atrial fibrillation, and diseases of the blood vessels (such as atherosclerosis) all increase stroke risk. Thankfully, many of these can be monitored closely and managed by working with your doctor.
Other stroke risk factors such as smoking, poor diet, and a sedentary lifestyle are within your control to address, thereby reducing your risk of stroke.
The American Stroke Association is a wonderful resource for understanding stroke risks and symptoms. You can learn more about the factors that increase your risk for stroke (and what to do about them) by visiting this page on their site.
Is Frontotemporal Dementia Hereditary?
One of the trickiest types of dementia to diagnose, frontotemporal dementia oftentimes doesn’t show itself with classic dementia symptoms. That’s because this type of dementia specifically impacts the frontal and temporal lobes of the brain.
But what does that mean?
The human brain is separated into four primary lobes, each of which are responsible for some crucial functions. Here’s a handy guide that shows the lobes of the brain and simplifies their primary roles.
The frontal lobe is the biggest lobe of the brain, and the one that takes up the front portion of your head. This lobe has several key functions, chief of which are regulating your personality and behavior, and supporting your decision making, reasoning, and movement skills.
The temporal lobe lives around your ears, and is responsible for understanding and processing language, as well as your short term memory and visual processing skills.
Because frontotemporal dementia (FTD) impacts the functioning of these two lobes of the brain, it’s often characterized by changes in personality, behavior, thinking skills, and communication abilities.
Dementia researchers have found this dementia is caused by mutations in five particular genes.
Currently, scientists are most interested in investigating mutations on chromosome 9, which they believe strongly contribute to this condition’s inheritable components.
While there’s still ongoing debate about the precise hereditary underpinnings of FTD, around 30% of people diagnosed with this condition have a strong family history of this type of dementia.
Therapeutic clinical trials are underway to assess risks and work to develop precision treatments for those at risk for developing FTD.
Is Lewy Body Dementia Hereditary?
Caused by the toxic effect of an abnormal protein in the brain, Lewy body dementia was originally conflated with other types of dementia, before being recognized as a separate type.
Lewy bodies are the name given to the abnormal structures found in the parts of the brain that control movement, emotion, judgment behavior, and awareness. Issues with these functions get progressively worse as Lewy bodies accumulate over time, severely impacting the brain.
While the exact causes of Lewy body dementia (LBD) are unknown, environmental, lifestyle, and genetic factors are believed to play a role in those who develop this condition.
It should be noted, however, that Lewy body dementia is not believed to have a strong genetic component.
While a very small number of cases may be linked to hereditary factors, LBD on the whole is not known to be hereditary.
As with other types of dementia, however, those with a family history of LBD may be at increased risk for developing this condition. Current research efforts are actively investigating the hereditary and genetic components of LBD, in order to offer more insight into the underlying causes of this condition.
Dementia and Genetics—A Complex Picture
While it’s clear genetics plays a strong role in some types of dementia, it’s often difficult to discern how its part plays out.
That’s largely because dementia is such a complex condition, arising from many different sources.
So, when it comes to asking the question, is dementia hereditary, the answer isn’t crystal clear, but we do know quite a bit.
One thing we know for certain is that while genetics is often a piece of the puzzle, it is not the entire picture.
What’s clear with most types of dementia is this multifactorial condition typically results from an amalgam of environmental, personal, familial, and lifestyle factors—rather than one singular causation.
While the majority of dementia types have not been found to have a strong hereditary component, you may still have concerns about your personal risks for developing dementia.
This article from The Alzheimer’s Society offers readers a deep dive into the genetic components of dementia. You can also open lines of communication with your doctor or another trusted healthcare professional to assess your risks and, if warranted, pursue next steps.
Genetic testing is available in some cases to assess risks, but it’s often best to first look into genetic counseling services to help understand this complex process and interpret your results.
While it’s proactive to educate yourself and understand your risks when it comes to your health and wellness, it’s important to know—having a close family member with dementia doesn’t mean you’re destined to develop this condition too.
Because dementia is multifaceted, you can help mitigate your concerns by managing any risk factors for this condition that are within your power to control. This includes addressing any unhealthy habits and lifestyle choices, staying active, and finding ways to challenge your brain each day.
This way, even if you have some genetic risks in your family, you can reduce the chances these risks will ever become reality.
At WayWiser, it’s our mission to offer quality information and assistance to older adults and their loved ones. With our Word to the Wise blog, we strive to address topics of interest to you and your family. If you are currently caring for a loved one, consider WayWiser’s app as a solution for your coordination and communication needs.