Is dementia hereditary?

How genes affect dementia risk

Alzheimer's Research UK describes dementia risk as a complex mixture of factors, including age, genes, health, lifestyle and environment. Genes affect risk in two quite different ways.

Risk genes

Some genes change the chance of developing dementia without deciding it. APOE is the best known. Carrying a risk gene does not mean you will develop dementia.

Genes that cause dementia directly

A small number of rare gene changes cause dementia directly. They usually lead to dementia at a younger age and affect several generations of a family.

If a parent or grandparent had dementia

Alzheimer's Society says that a parent or grandparent developing Alzheimer's disease in their 70s or 80s does not change your risk compared with the rest of the population. The NHS says the genes you inherit can contribute to your risk, but the increase is small.

It is different when dementia starts young. About 3 in 100 people with Alzheimer's disease develop it before the age of 60, and in these cases a faulty gene is much more likely to be the cause.

If several relatives developed dementia at a young age, talk to your GP, who can refer you to a genetics service.

Inheritance by type of dementia

• Alzheimer's disease: In more than 99 in 100 cases, it is not inherited.
• Vascular dementia: In most cases, it is not inherited, although some of its risk factors, such as high blood pressure and diabetes, can run in families.
• Frontotemporal dementia: It is inherited more often. About 40 per cent of people who develop it have at least one close relative diagnosed with some kind of dementia, and the behavioural form is the one inherited most often.
• Rare inherited conditions: Huntington's disease and familial prion disease are each caused by a single faulty gene, with a 1 in 2 chance of it being passed on.

The APOE gene

Everyone carries the APOE gene, in one of several versions. The e4 version is the one most linked with a higher risk of Alzheimer's disease. The more copies of e4 someone has (none, one or two), the higher the risk.

APOE does not cause dementia directly. Many people with e4 never develop Alzheimer's disease, and many people without it do. An APOE result cannot tell you whether you will develop dementia, or when.

Dementia caused by a single gene

In a few families, dementia is caused by a change in a single gene. If someone carries one of these changes, each of their children has a 1 in 2 chance of inheriting it.

• Familial Alzheimer's disease: Usually caused by a change in one of three genes, PSEN1, APP or PSEN2. PSEN1 causes about 4 in 5 cases, and symptoms can begin as early as the age of 30.
• Familial frontotemporal dementia: Linked to changes in at least nine genes, most often GRN, MAPT and C9orf72.
• CADASIL: A rare inherited form of vascular dementia, diagnosed on average at about the age of 50.

Families affected by these conditions may find genetic counselling helpful before deciding whether to have a test.

Genetic testing

On the NHS

The NHS does not test for dementia risk genes such as APOE. NHS genetic testing for dementia is usually offered only when there is a very strong family history, through a memory clinic or a clinical genetics service.

Privately

We offer testing for the APOE gene, other single genes and a panel of 35 genes linked to dementia and Parkinson's disease, with a consultation before the test. People consider testing for different reasons, such as a family history of dementia or wanting to plan ahead. Some decide not to test.

If you are worried about memory changes now, a dementia assessment is the way to find out what is causing them. A genetic test cannot tell you.

• Genetic testing for dementia
• About the dementia assessment

Questions about dementia and genes

Is Alzheimer's disease hereditary?

In more than 99 in 100 cases, Alzheimer's disease is not inherited. In a small number of families, a single faulty gene causes it, usually at a younger age.

If my parent has dementia, will I get it?

Not necessarily. Most dementia is not inherited, and age, health and lifestyle all play a part. If several relatives developed dementia at a young age, talk to your GP about a referral to a genetics service.

Is there a test for the dementia gene?

There is no single dementia gene. A genetic test can look at risk genes such as APOE, or at genes that cause rarer inherited forms of dementia. It cannot tell you whether you have dementia now.

Can I get genetic testing for dementia on the NHS?

Usually only when there is a very strong family history, through a memory clinic or a clinical genetics service. The NHS does not test for risk genes such as APOE.

Sources

1. Alzheimer's Society: Is dementia hereditary?Checked 29th September 2026
2. Alzheimer's Society: Can genes cause dementia?Checked 29th September 2026
3. Alzheimer's Society: Rare types of dementia caused by genetic changesChecked 29th September 2026
4. Alzheimer's Research UK: Is dementia hereditary?Last updated November 2024
5. NHS: Alzheimer's disease, causesLast reviewed 4th July 2024