Experts generally agree that there is no single cause of dementia and that it is the result of many factors coming together to cause the brain cells (neurons) to slow down. And, the different dementia diagnoses have different initial causes.
Proteins in the Brain
In some cases, protein clumps can slow down or kill neurons in the memory circuits.
- Alzheimer’s dementia, for example, is caused by certain naturally occurring proteins such as amyloid and tau.
- Frontotemporal dementia is associated with tau protein clumps.
- Lewy body dementia is associated with synuclein-containing clumps.
Reduced Blood Flow
In other cases, it may be a small or big stroke that causes poor blood flow to parts of the brain. Vascular dementia, for example, is caused by poor blood flow to neurons in the brain
Dementia and Genetics
Genes are like recipes to build your body, and just like any recipe, the ingredients and the method of making the food impacts the final result. How your body interacts with the environment (lifestyle), how you take care of your body (food & toxins), and how you cope with the world (stress & happiness) will play a much larger role in shaping your risk of dementia.
Familial Patterns
Some conditions, such as Late Onset Familial Alzheimer’s Disease, tend to occur in families more often than by chance or seen in the general population. This form appears after age 65 and does not follow a simple inheritance pattern. Instead, it likely involves a combination of several genetic factors and shared environmental or lifestyle factors within families. While having family members with Late Onset Familial Alzheimer’s Disease increases a person’s risk of developing the disease, it doesn’t guarantee they will develop the disease.
Hereditary Forms of Dementia
There are some types of dementia that follow a clear inheritance pattern caused by gene mutations. These diagnoses are much rarer than others, but they do exist.
Huntington’s Disease is a disorder that can cause dementia, and it is only caused by inheriting a genetic mutation. Specifically, it is caused by a mutation in the HTT gene. A child of a parent with the gene mutation has a 50% change of inheriting the gene, and therefore the disorder.
Early Onset Familial Alzheimer’s Disease is a hereditary form of the disease that appears before age 65 and follows a clear inheritance pattern. It is caused by mutations in one of 3 genes (APP, PSEN1 or PSEN2). If a parent has one of these mutations, there is a 50% chance they will pass the gene mutation to their child, who will then likely develop Alzheimer’s before age 65.
