The importance of genetics in dementia is not well understood. Dementia mostly occurs at random. Usually, it's not directly caused by a single gene, and there is usually no clear pattern to indicate that somebody has inherited dementia from their parents.
If you have a close relative with dementia, the risk of your getting it is only slightly higher than it is for other people.
But there are some rare types of dementia that can be caused directly by an inherited change in a single gene. A change in a gene is called a gene mutation.
These rare, inherited types of dementia include:
- Familial Alzheimer’s Disease (FAD)
- a type of dementia caused by reduced blood flow to the brain known as CADASIL
- Huntington’s disease
- frontotemporal dementia (some forms only).
If a parent has the mutated gene that causes FAD, CADASIL or Huntington’s disease or some forms of frontotemporal dementia, then each child has a 50% chance of inheriting it. If they do inherit the gene, they will develop dementia, often in their middle age.
Deciding whether to have a genetic test or not is difficult. You might naturally want to know if you have a high risk, but there are downsides to knowing too. It is essential to have specialised genetic counselling before deciding to have a genetic test. You can discuss genetic counselling with your doctor or call the National Dementia Helpline on 1800 100 500 to arrange an appointment with a counsellor.
Last reviewed: January 2017