We are often asked about the genetics of dementia – whether diseases like Alzheimer’s can be inherited, or passed down through families. Most cases of dementia are not directly caused by genes.
The word dementia describes a group of symptoms including memory loss, confusion, mood changes and difficulty with day-to-day tasks.
There are a number of different types of dementia, including Alzheimer’s disease, vascular dementia, dementia with Lewy bodies and frontotemporal dementia.
You can read more about the different types of dementia here.
There are two different types of genes which play a role in dementia:
Dementia is common, so many of us have relatives with a disease like Alzheimer’s. But this does not mean we will definitely develop it too.
99 out of 100 cases of dementia are not directly caused by genes we inherit from our parents. In most cases the likelihood of us developing dementia, is made up of a complex mixture of factors.
The includes our:
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age
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genes
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health
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lifestyle
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and environment.
Risk genes
The DNA code in our genes naturally varies from person to person. Often this variation has no effect on us. But sometimes our genes contain variations that alter the protein made by a particular gene, causing it to work differently.
This can change the way our cells work, which can increase (or sometimes decrease) our likelihood of developing a disease.
These variations are known as risk genes, and some are involved in the development of dementia.
We might inherit risk genes from our parents, but this does not mean we will definitely get dementia.
This is because our risk of developing dementia is usually a combination of our risk genes, lifestyle, environment and age.
It also means that people without any dementia risk genes can still get dementia too.
Faulty genes
In very rare cases, a person may inherit a gene that does not work properly from one of their parents.
This faulty gene, sometimes called a mutated gene, can cause a person to develop a disease no matter what other risk factors they have.
Around one in 100 cases of dementia are caused by faulty genes. People who carry these faulty genes normally develop dementia at a younger age, before they are 65.
If people with these faulty genes have children, there’s a one in two chance of passing the faulty gene to their child. If a child of a parent with the faulty gene doesn’t inherit it, they will not carry the gene or pass it on to their own children – these faulty genes don’t skip generations.
In these rare families, a mutation in one of these genes causes dementia, often at an early age. These are single gene disorders.
The rest of us have changes in many genes that contribute a small amount to our overall risk.
- Professor Nick Fox, Director of the Dementia Research Centre at UCL
Genes and dementia
The booklet gives an overview of what genes are and how they are involved in the different diseases that cause dementia, along with information on genetic testing and current research.
Order health information
Alzheimer’s Research UK has a wide range of information about dementia. Order booklets or download them from our online form.
Dementia Research Infoline
Do you have questions about genes and dementia? Or are you keen to get involved in research studies?
Contact the Dementia Research Infoline
9am-5pm, Monday to Friday
0300 111 5 111
This information was updated in November 2024 and is due for review in November 2026. It does not replace any advice that doctors, pharmacists, or nurses may give you. Please contact us if you would like a version with references.
This information is produced with support from The Perfume Shop who had no input into the content.
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