Genes
Apart from some rare cases, most instances of dementia are not inherited. But we can inherit certain genes from our parents that make us more vulnerable to developing dementia.
The best understood risk gene is ApoE4. You can inherit this gene from your mother or father or both parents.
6 out of 100
75 year-olds with no copies of ApoE4 gene will have dementia.
Inheriting two copies of the ApoE4 gene is quite rare – fewer than 2 people in every 100 will.
If you do, it doesn't mean that dementia is inevitable for you. Lifestyle choices that you make can play a role too.