Is Dementia A Heritable Condition?

Dementia is rather common in the elderly population, and for many decades medical professionals assumed that this cognitive decline is nothing more than a consequence of getting older. However, it turns out that the picture is more complex.

Apart from some rare cases, there are no specific genes for dementia. This is not a disease programmed in our genome. However, if one of your parents or grandparents was suffering from dementia, your risk of getting this condition at an older age is definitely higher.

How can dementia be inherited?

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Although dementia is not heritable, some genes or their combinations may cause a predisposition to this condition. For instance, various studies put the heritability of Alzheimer’s disease, the most common form of dementia, at around 70%.

Late-onset Alzheimer’s is most commonly linked to certain variants of gene ApoE. ApoE E4 allele is known to increase the risk of dementia, while ApoE E2 reduces this risk. However, not every carrier of ApoE E4 gets dementia, and lots of people who do not have ApoE E4 still develop Alzheimer’s disease.

Many of the genes that may influence the chances of developing dementia have very little to do with our mental abilities. In fact, some of the most influential molecular factors in this respect are related to the genes and proteins responsible for the removal of molecular wastes from the brain cells.

This deals with the fact that neurodegenerative diseases behind dementia are caused by the accumulation of toxic protein aggregates that interfere with the normal functions of neurons. Factors that increase the accumulation of toxic protein aggregates increase the chances of dementia. These factors might be completely unrelated to the brain health and influence the risk of dementia very indirectly.

However, we have to remember that the term “dementia” does not refer to a specific disease. A decline in the cognitive abilities may be caused not only by the development of Alzheimer’s disease but also by multiple other neurodegenerative conditions. Huntington’s disease-linked dementia, for instance, is highly heritable.

How can dementia be prevented?

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Genetic predisposition to dementia does not make it unavoidable. Certain lifestyle modifications were proven to reduce the risk of this condition or slow down its development. Having a job that involves mental tasks reduces the risk of dementia later in life. So does the healthy lifestyle and diet.

Even in the case of highly heritable Huntington’s disease, it was demonstrated that regular physical exercise helps to postpone the onset of the disease.

On the other hand, high blood pressure increases the risk of vascular dementia. Chronic stress and depression were also associated with higher chances of getting Alzheimer’s disease at an older age.

Recent discoveries about the causes and risk factors of dementia point to strong genetic components in the development of this condition. However, genes only predispose a person to the development of dementia. In the majority of cases, the contribution of various environmental and lifestyle factors is needed to trigger the disease development. Knowing the risk factors can help in reducing the chances of dementia at an older age. It can also help in managing the patients more effectively and slow down the disease progression.

Like with any other chronic condition, early detection is important for better treatment and management of dementia. The BrainTest® app can help in detecting the early signs of cognitive decline. Timely identification of problems allows slowing down the development of the disease.

Dr. Viatcheslav Vlassov received a Ph.D. in Biomedical Sciences and worked as a researcher and lecturer at several universities around the world, including the University of Cambridge, the University of New South Wales, and the University of North Carolina. In his current role as a scientific consultant, he provides academic technical support and lends his expertise to researchers, organizations, and individuals working in various fields of biological, chemical and medical sciences.

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