Since most cases of dementia are caused by a complex mixture of factors, the NHS only offers genetic testing in rare, specific circumstances.
Genetic tests can be used to tell whether someone has inherited a gene linked to a particular disease, and to estimate their chances of developing that disease later in life. This page will cover genetic testing for risk genes and genetic testing for faulty genes.
Genetic testing for risk genes
Genetic testing that looks for genes that increase our risk of dementia is not currently available on the NHS. This is because most of the genes discovered so far only have a relatively small effect on someone’s overall risk of developing a condition like late onset Alzheimer’s disease.
Many people who inherit these genes will not develop dementia and equally, people who do not have risk genes can still develop it.
Genetic testing for faulty genes
Having a test to look for a faulty gene that causes dementia is only appropriate in certain circumstances. This is because directly inherited dementia is rare, accounting for only one in 100 cases.
If you are worried that you have a strong family history of young onset dementia, you can speak to your doctor about this.
Deciding to take a genetic test to see if you have an inherited type of dementia is a big decision and needs very careful thought. Some people may not wish to know if they carry a faulty gene that causes dementia. Others may feel it would help them and their families to plan for the future.
If a test is appropriate, your doctor should refer you to a genetic counsellor or specialist. This could be a cognitive neurologist or memory clinic psychiatrist.
Some examples of faulty genes that a genetic test may look for, and the type of dementia they cause, can be seen in the table below.
| Gene | Associated disease |
|---|---|
| APP | Familial Alzheimer's disease |
| PSEN1 | Familial Alzheimer's disease |
| PSEN2 | Familial Alzheimer's disease |
| MAPT | Familial frontotemporal dementia |
| GRN | Familial frontotemporal dementia |
| C9orf72 | Familial frontotemporal dementia |
| NOTCH3 | CADASIL and vascular dementia |
| SNCA | Familial dementia with Lewy bodies |
| SNCB | Familial dementia with Lewy bodies |
My mum died with frontotemporal dementia (FTD) caused by the faulty MAPT gene, which I had a 50 per cent chance of inheriting. Unfortunately, I discovered that I had inherited the gene, so will go on to develop FTD.
When I got my test result, it was an incredibly tough thing to hear, but there was also a massive sense of relief. Not knowing was a burden I could not live with. At least I now feel I know what the shape of my life will be. I can make plans and make choices to live a fulfilled life. I feel like the diagnosis is actually a licence to live.
- Jordan Adams, who decided to take a genetic test because of his strong family history of young onset frontotemporal dementia.
Our video series “Genetic testing for dementia” includes a film containing first-hand accounts of being tested for genetic forms of dementia, and a series of frequently asked questions, answered by Prof Nick Fox, Director of the Dementia Research Centre at UCL. You can find the playlist below.
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.
Was this information helpful?
Let us know what you think by filling out this short survey.