- Alzheimer's disease: The situation depends on whether someone has early or late-onset Alzheimer's. A very rare type of early-onset AD exists that definitely runs in families, with some members developing symptoms as young as 30. This type is caused by a mutation in the gene that makes amyloid protein, which is responsible for the plaques and tangles that form in sufferers' brain cells. People in these families are advised to see their doctor to arrange genetic testing.
In the case of late-onset dementia, you may possibly but by no means definitely develop AD if you have a relative with the condition. The gene responsible is apolipoprotein E (APOE for short), which is found on chromosome number 19. This gene has four variants, and the likelihood of the disease being passed on depends on which of these variants a person has.
- Vascular dementia: No proven genetic risk exists for most cases of vascular dementia, although its associated risk factors, such as heart disease, diabetes, and strokes can run in families. The only exception to this is CADASIL, which is a rare genetic form of the condition.
- Frontotemporal dementia: In contrast to vascular dementia, a risk of frontotemporal dementia runs in families. Researchers have identified genes for two different abnormal proteins that could be responsible for this. It's believed that around 40 percent of people with frontotemporal dementia have a family history with it.
- Lewy body dementia: No clear answer can be given to the question of whether a genetic component exists in the development of this form of dementia. Some overlap in genetic mutations with those who have AD and Parkinson's disease is thought to be evident, but no one can yet say for certain.
If you have a close relative with frontotemporal dementia, seek genetic counseling via your primary care physician.
Dementia doesn't discriminate. It affects people from all ethnic backgrounds. In the United States the numbers of people from certain ethnic groups do appear low, but that may be the result of other factors, including- Access to diagnostic services
- Poor experiences when seeking help from primary care physicians
- Cultural understanding of the condition
- Stigma attached to being given the diagnosis