If several members of your family have developed the disease, you might be asking yourself is dementia hereditary? Unfortunately, there is no definitive answer as it very much depends on what the root cause of the dementia is.
There are several different causes of Dementia. Some are known to be hereditary; a few types of dementia are both inherited and non-inherited; and others are never inherited.
Is dementia hereditary?
The type of dementia caused by Huntington’s disease is very much hereditary and you only need one copy of the faulty gene to inherit the disease. Huntington’s disease is a progressive disease and the symptoms usually begin to manifest themselves in adults when they reach their thirties, although there is a variation of the disease that affects children. The form of dementia seen in patients with Huntington’s is different to the more common type of dementia associated with Alzheimer’s as sufferers are still able to recognize people and places.
Is dementia hereditary when related to Alzheimer’s?
Alzheimer’s disease is the most common type of dementia and although there is certainly a genetic factor in some cases of Alzheimer’s, there are also many other risk factors known to be responsible.
In the majority of cases, dementia caused by Alzheimer’s disease begins to show itself in later life and most cases are seen in people aged 65 and over. In some families, there are indications of a genetic factor, but this is usually in families where symptoms of the disease appear at an earlier age. For the rest of the general population, if your parents or other close relatives develop Alzheimer’s related dementia, the odds on you developing the disease in later life are only slightly higher than average.
In the case of early onset dementia caused by Alzheimer’s disease, there is very often a clear genetic link passed down through family generations and research into Alzheimer’s has discovered faults on three genes that affect the risk of developing Alzheimer’s disease: chromosome 21, chromosome 14, and chromosome 1. However, these high-risk gene mutations are very rare in the general population and only a small group of families are affected worldwide.
Other gene mutations known to affect the incidence of Alzheimer’s related dementia include one which leads to a rare form of vascular dementia. Another form of inherited dementia is Pick’s Disease.
There are many more genetic faults in existence that are known to be related to the development of dementia, including the presence of the three types of apolipoprotein E. Depending on what combination of this gene you end up with, your risk of developing Alzheimer’s later in life can be increased by as much as ten times.
But if you are concerned about the genetic factors related to the development of dementia, you must remember that in the vast majority of cases, it is purely down to chance whether or not you develop the disease. However, if two or more close relatives develop dementia related to Alzheimer’s before the age of 60, you can be referred for genetic counseling and further tests if appropriate.