Usually, genetics can only increase your risk of developing dementia but not directly cause it. But there is a rare type that is passed down in families.
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There are multiple risk factors for dementia, including family history. Many families carry a gene that can increase the risk of developing dementia — but not a gene that directly causes dementia.
You’re more likely to have genes that increase your risk of dementia if you have a family member who developed dementia before they turned 60 years old, or if you have a parent or sibling who developed dementia.
Genetic testing can help you get a more complete picture of your potential risk.
The risk of dementia can run in families. However, it’s rare for dementia itself to be passed down genetically. This might sound confusing but it’s because of the different types of genes that can lead to conditions such as dementia.
There are four genes known to increase your risk of developing dementia, and these genes do run in families. But this doesn’t mean dementia is an inherited condition. Many people with these genes never develop dementia, and many people without these genes do develop dementia.
What kind of dementia is hereditary?
The type of dementia passed down in families is a very rare type of Alzheimer’s disease called familial Alzheimer’s disease (FAD). Less than 1 percent of all cases of dementia are caused by this inherited gene.
A parent with the gene for FAD has a 50% chance of passing it to their child. People with the FAD gene typically develop Alzheimer’s in their 40s or 50s.
Genetic testing can help you look at possible risks in your family. If people in your family have any form of dementia, looking at how many people have it and the ages they developed it can help you assess risk.
For instance, although anyone can develop dementia, the risk is known to be higher if you have:
- a family member who developed dementia when they were younger than age 60
- a parent who developed dementia
- a sibling who developed dementia
It’s also a good idea to talk with a doctor about your possible risk of developing dementia. Family history can sometimes give you an idea of risk, but it’s not a reliable indicator.
If you’re interested in taking a test to see if you have any genes that increase your risk for dementia, you can learn more in our guide to at-home genetic testing.
Some genes and gene abnormalities make it more likely that you’ll develop a condition, but don’t necessarily mean you will get that condition. These genes don’t cause a condition, they just put you at higher risk.
One important gene that increases the risk of dementia is called Apolipoprotein E. This gene is carried on chromosome 19. Everyone carries two of these genes in pairs, one inherited from each parent.
The more copies of this gene you carry, the higher your risk of developing some form of dementia.
It’s a good idea to talk with a doctor if you’re concerned about your dementia risk. You can also make lifestyle adjustments at home.
Some lifestyle changes may help you live a healthier life and even lower your overall risk of developing dementia, even if you have a genetic risk.
This includes:
- getting adequate sleep every night
- quitting smoking
- getting at least 150 minutes of exercise each week
- following a nutritious diet that is heavy in fruits and vegetables
- eating less processed meats, sugars, and refined grains
- maintaining a healthy weight for your body and avoiding obesity
- staying mentally active
- avoiding social isolation
Having a family member with dementia can increase your risk of developing dementia. The risk goes up if your family member developed dementia before they turned 60 years old or if the family member is a parent or sibling.
There are also genes that make it more likely that someone will get dementia that can be passed along in families. However, having these genes does not mean you will develop dementia. Many people with these genes never get dementia, while many without them do develop the condition.
A rare type of dementia called familial Alzheimer’s disease is caused by a gene that is passed down in families. This gene directly causes dementia and is inherited in family lines.
If you’re concerned about dementia in your family, genetic testing can show you if you have any genes known to increase the risk.