Is vascular dementia hereditary?
We know a great deal about Alzheimer’s disease and its hereditary components. Less is known about the second most common form of dementia: vascular dementia. But what exactly is vascular dementia? What are the possible causes of this disease? And is vascular dementia hereditary? iGene provides the answers.
What is vascular dementia?
Damaged blood vessels can cause part of the brain to receive less blood and, as a result, to gradually die. If the resulting cognitive problems are so great that they impair a person’s ability to function on a day-to-day basis, we talk of vascular dementia. The disease generally develops between the ages of 65 and 75, but vascular dementia can also occur at a younger age. Out of all the people affected by dementia, approximately 10 to 15% have vascular dementia.
Causes of vascular dementia
Vascular dementia has various causes. These can provide a greater insight into whether vascular dementia is hereditary.
The main risk factors for vascular dementia are age, lifestyle and genes. If a person has had a stroke or suffers from diabetes or a heart condition, he or she is twice as likely to develop vascular dementia. Vascular dementia can develop as a consequence of small strokes or TIAs, but can also occur after just a single cerebral infarction. If you have ever suffered from depression, this also increases your risk of vascular dementia.
Vascular dementia is a consequence of damage to the blood vessels in the brain. This means that, by and large, the same (genetic and non-genetic) risk factors that we know from a stroke or cardiovascular diseases also play a role.
There are certain genetic mutations that can significantly increase the risk of vascular dementia. This is the case, for example, with the rare condition CADASIL (‘Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy’). People affected by this condition frequently suffer from (often recurrent) strokes in middle age. These recurrent strokes increase the risk of vascular dementia.
In the case of CADASIL a mutation in the NOTCH3 gene on chromosome 19 is responsible for the recurrent strokes. If a parent carries this mutation, there is a 50% chance that a child will inherit it. This mutation, which also leads to an inherited increased risk of vascular dementia via the strokes it causes, is very rare and occurs in the Netherlands in only slightly more than 170 families (source: Hersenstichting).
Another example of a condition where a genetic mutation results in an inherited increased risk of vascular dementia is Katwijk disease (also known as HCHWA-D, Hereditary Cerebral Hemorrhage With Amyloidosis – Dutch type). Patients affected by this disease suffer their first cerebral haemorrhage or cerebral infarction between the ages of 45 and 65 as a result of an accumulation of proteins that weakens the vessel walls in the brain. This condition is also extremely rare. Worldwide there are only around 350 people who are known to have this condition, which also leads to an inherited increased risk of vascular dementia as a result of strokes.
We would like to stress once again that conditions linked to an inherited increased risk of vascular dementia, as in the examples above, are extremely rare. Together they are responsible for only a very small proportion of all vascular dementia cases.
Is an increased risk of vascular dementia hereditary?
In addition to rare mutations that significantly increase the risk of vascular dementia, there are also more common genetic variants that can (very) slightly increase or reduce this risk. These genes, which make you slightly more or less susceptible to vascular dementia, are similar to those that increase or reduce your risk of cardiovascular diseases.
Are cardiovascular diseases or strokes relatively common in your family? If so, it is possible that you have a slightly increased risk of vascular dementia. Please note: this does not mean that vascular dementia is hereditary in the sense that you inherit it directly from your parents. However, it does mean that a slightly increased risk of developing vascular dementia can be inherited. To put this in perspective, heredity plays a much smaller role in the case of vascular dementia than it does in the case of Alzheimer’s disease, for example.
Preventing vascular dementia
What can you do yourself to reduce the risk of vascular dementia? Broadly speaking, you can do the same things that prevent cardiovascular diseases or a stroke (or at least reduce your risk of developing these conditions). After all, if you look after your heart and blood vessels, you will also reduce your risk of blood clots that could block the supply of blood to part of the brain. An iGene Passport gives you an insight into your risk of developing these and other conditions and offers you advice on how to reduce this risk.