“I will be turning sixty-five in a couple of months and the thought of any kind of dementia scares the living daylights out of me.”
‘I am 62 years old and really concerned as the life of the mind is everything to me.’
Have YOU ever felt like that?
Someone in your family has been diagnosed with Alzheimer’s disease
And you are scared that YOU will get it too?
Here are the facts as they are known now.
Alzheimer’s disease is not usually hereditary.
In 99% of the cases Alzheimer’s is not caused by the genes received from a person’s parents. Professor Nick Fox, Institute of Neurology, London
Even if several members of a family have in the past been diagnosed as having Alzheimer’s disease, this does not mean that a further member of the family will necessarily develop it.
The dominant risk factor for Alzheimer’s disease is age; so everyone risks developing the disease at some time. The odds are only marginally increased by having a parent or grandparent with Alzheimer’s disease.
It is now known that there is a gene, which can affect this risk. This gene is found on chromosome 19 and it is responsible for the production of a protein called apolipoprotein E (ApoE). There are three main types of this protein, one of which (ApoE4), although uncommon, makes it more likely that Alzheimer’s disease will occur.
However, it does not cause the disease, but merely, for a person aged 50, increases the likelihood of developing Alzheimer’s disease from the usual 1 in 1,000 to 2 in 1,000. And that 50-year-old might never actually develop it. Only half of people with Alzheimer’s disease have ApoE4 and not everyone with ApoE4 suffers from it.
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Some (rare) causes of dementia are very clearly ‘inherited’, for example Huntington’s disease. This is an ‘autosomal dominant’ disease which means that only one faulty copy of the gene is needed in order to inherit the disease.
If you have inherited the gene you will get the disease if you live long enough. It does not skip a generation. Some other dementias have both inherited and non-inherited forms. In the case of fronto-temporal dementias, 30 to 50 per cent of cases are inherited.
Remember, most cases of Alzheimer’s disease are NOT inherited.
Thank you for answers to questions. I find it very interesting .
I am the youngest of 8 children, my father diagnosed as old age senility, my mother dementia, 1 sister alzheimers, 1 brother lewy body dementia, 1 brother vascular dementia, 1 sister vascular dementia, 1 sister brain tumor, 1 brother cognitive disorder and early time dementia (69, living) and 1 brother killed at 34 years, so the likelihood of me aged 67 must be 99% chance of getting this terrible disease. DO YOU REALLY THINK IT IS NOT GENETIC??????
Thank you for your response and it is natural that you are worried! There is still a lot of research being done in this area, of course, but the current consensus is that having a close relative with the Alzheimer’s disease is NOT evidence of a genetic link. Even people who are influenced by risk factor genes have only a slightly increased risk of developing the disease than the average population.
Here is a summary of what research is telling us.
Researchers at the University of Reading in the UK indicate that the most important gene discovered to date is the Apolipoprotein E (APOE) gene, which is found in chromosome 19. This gene occurs in three forms in humans: types 2, 3 and 4. Every person in the world carries two APOE genes: they can be the same type (2,2; 3,3 or 4,4), or a mixture of two types (2,3; 2,4; 3,4).
What has been found is that people with at least one type 4 and especially those with two, such as 4,4, are at a slightly increased risk of developing Alzheimer’s disease earlier in life than those with the other types of Apolipoprotein E. Only 2% of the population (in the UK) have two type 4 genes. And it seems that less than half of the 2% show increased occurrence of AD.
People with type 2, especially 2,2, appear to be protected against developing Alzheimer’s disease, until much later in life. Researchers do not understand why this is so, and there is much research underway to find out why.
What it all means is that the type of Apolipoprotein a person has is not enough on its own to cause Alzheimer’s disease.
When Alzheimer’s Disease IS Genetic:
Very early onset Alzheimer’s Disease can be caused by a Genetic mutation; that is a permanent change in a gene that can be passed on to children. The rare, early-onset familial form of Alzheimer’s disease is associated with mutations in genes on chromosomes 21, 14, and 1. This condition is very rare indeed, and the families where it occurs are known to the medical profession in most countries. It is known as Familial Alzheimer’s Disease.
Lifestyle factors matter so looking after the basics is important for everyone. Daily exercise, a heart-healthy diet, giving up smoking and plenty of daily mental challenges.
My mother and two of her sisters had dementia. They said one had Alzheimer’s and my mother had dementia. What’s the difference?
Hello, Mary – yes these terms are often used as interchangeable, which they are not. Dementia is the overall term but there are several pathways to dementia – Alzheimer’s Disease being the most common. this article will help you understand the difference more clearly: https://www.brainfit.world/2013/11/03/is-it-dementia-or-alzheimers/
What about somebody who got diagnosed in 2017 at age of 57? Would this person’s child develop it? Neither that parent or child (under age of 30) are proactive…
You may be interested in a free online course that gives you the latest research that is going on. It is a very good course and would help you with the further queries you have. http://www.utas.edu.au/wicking/understanding-dementia It is open to everyone and starts next week (February 19th)
I have three generations of relatives who have all had Alzheimer’s. My Great grandfather, I don’t know many details about him. Then both his children, my Grandmother and her brother both died of Alzheimer’s and now my father (an only child) who had obvious symptoms of Alzheimer’s at 55 and is in late stages now at the age of 70. So my fear is, although I recognize that my family is small, to date 100% of the relatives on my fathers side have gotten it and fairly young. How can I not be worried? How can I get tested for the inherited form?
Dr Allison Lamont replies: ‘I can see how worrying this is for you. It is true that early onset Alzheimer’s has a little bit more of a genetic component, but it is very, very far from inevitable.
There is a lot that is in our own hands, too. The Lancet, a world-respected medical journal published a paper this month making it clear that we can lessen our risk factors for Alzheimer’s by up to 35%. This is by our lifestyle factors: keeping the brain humming along by a variety of brain challenges, moderate exercise, good nutrition, keeping socially engaged, having a positive and interested attitude to everything we do, making sure we have plenty of sleep, and definitely having self-belief that we can make a difference to our own futures. These things are definitely worth doing! As far as genetic testing goes, there isn’t a test that I am aware of that would give you the information you want. Any test will be for the presence of APOE-e4 gene but the results are very difficult to interpret and most specialists don’t recommend it. We can have two copies of the APOE-e4 gene and not develop Alzheimer’s so it can be really confusing. For all of us, we can do everything we can to lessen our risk factors. It is important we look after both our body and our brain.’