Webinar: Genetics, Dementia and Families
Dementia Australia webinars are free videos where subject experts discuss topics relating to dementia for a general audience.
Have you wondered about the genetics of dementia? Some people are concerned about a family history of dementia and whether there could be any hereditary factors.
In this webinar, genetic counsellor Adrienne Sexton presents a brief overview of the genetics of Alzheimer’s disease and other types of dementia. She answers common questions about family histories, genetic testing and things people consider before deciding on a gene test.
This webinar will also talk about genetic counselling and how it can help people with dementia and their family members.
You will learn about:
- genetic counselling for dementia, and how it can be helpful for addressing worries and providing information for relatives
- options for genetic testing and answers to common questions
- genetics for families with younger onset dementia or later onset dementia.
Transcript
[Beginning of recorded material]
[Title card: Genetics, Dementia and Families. Dementia Australia]
Adrienne: Hello, my name's Adrienne Sexton, and today, I'm talking about genetic counselling for people with dementia, and for people who have family members who have dementia. I work at the Royal Melbourne and Epworth, and I'm a genetic counsellor at those hospitals. Before I start, I'd like to acknowledge the traditional custodians of all the lands and waters from which we join this meeting today, and to acknowledge their continuing culture and connections to countries since time immemorial. I'm on the land of the Wadawurrung people, and I pay respects to their Elders, past and present. And I extend that respect to all First Nations people who might be listening to this webinar today.
This webinar is for people who have dementia, and also for family members of people with dementia. And we're going to cover questions such as is dementia genetic? What's genetic counselling? What's involved, and how can it help? I'm going to give some examples of what people say about their experience of genetic counselling and genetic testing. I'm going to talk a little about why people consider genetic testing for dementia. Sometimes, there is a genetic basis to dementia, and that can be particularly the case when dementia symptoms start at younger age. I'm not going to talk about childhood dementias today because those have separate genetic basis, but I'm going to focus on adult-onset dementia, and young-onset dementia is when symptoms start under 65.
Young-onset Alzheimer disease can sometimes have a genetic cause, particularly if symptoms have started under 50, and when there's a strong family history of Alzheimer's at younger age. Frontotemporal dementia at any age can sometimes have a genetic cause. Vascular dementia and dementia with Lewy bodies, though, are rarely genetic. There are some specific rare causes of dementia like Cadasil, which causes mini strokes, and/or major strokes, and causes dementia over time, and other conditions like Huntington disease, which has problems with movement and thinking, and has a specific gene, which is the cause of that. Dementia due to other conditions like leukodystrophy can also have a genetic cause, and there are some genes that overlap between causing motor neuron disease and dementia.
A lot of people do worry if they've got a family with Alzheimer's disease whether they will get Alzheimer's too in the future, but most of the time, that's not the case. Having a parent with Alzheimer's does not usually mean that you would get Alzheimer's. It does sometimes mean that there might be a higher chance, and if that's in older age, then the inheritance of that is much more complicated, and so, the chances of getting Alzheimer's are not very high but they may be a little more increased compared to average.
One of the major factors that you might have heard about in the media for Alzheimer's disease is the APOE gene, and we've all got two copies of this gene, and they come in different forms. Those forms are named APOE2, ApoE3, and ApoE4. So, we've got these combinations of two copies of APOE, and people who have APOE4 and APOE4 have the highest chance of getting Alzheimer's, but it's really important to know that this risk is mainly in quite late age, so in the 80s and 90s as you can see from this graph with the ages along the bottom there. People with one copy of APOE4 and different form on the other copy have an increased risk, but you can see that most people still would not get Alzheimer's in older age. So, with APOE, it can tell something about future risk of Alzheimer's, but that's mainly in quite late age.
I'm going to take a little step back now and just talk really briefly about genes and DN, and what are they – so every cell in our body, including all the cells in our brain, contains thousands of genes, 20,000 genes actually, and each gene is made up of a part of DNA code. So that holds the information that our cells need to make the proteins that make our brain and other parts of our body work. If there's a problem in the DNA code of the gene, then the cells can't make the protein properly, or the protein might be not made quite right and may build up, and there can be damage to the nerve cells and that can lead to dementia if the problem is in a gene linked with dementia. So, all our genes come in pairs, and we get one copy from our mum, and one from our dad. And in this example here, you can see that the father has one copy of a gene with a problem, and the other copy working normally. And so, that means that it's a 50-50 chance for each child of whether they've inherited the copy working normally or the copy with a problem. And we all inherit copies of gene problems down through many generations of our family.
Occasionally, this can be a problem in a dementia gene. Genetic counselling is something that a lot of people haven't heard about. It is mainly about communication about genetics, and it aims to help people understand and adapt to a possible genetic cause for a condition like dementia in their family. It's really guided by the person or the family who's coming to genetics, because everyone has different questions, different worries, and different reasons for coming to genetics, so it aims to really personalise the information, and to help them make decisions about genetics. It also aims to help link with extra support if needed, and to talk about how they might be able to tell their relatives about a genetic condition. You might like to watch the related webinars by Professor Amy Brodtmann, and also by Jane Smith in this series.
Some motivations for having genetic testing include to have an explanation for why it's happened. That can be really important to people just to have some sort of an answer for why young-onset dementia or dementia may have happened. And another key motivation is to have information for their family members, sometimes, that's for reasons of family planning, for whether there might be options for testing in pregnancy or IVF, but sometimes, it's more just so that people can know more about what their chance of dementia is, and have the opportunity to decide about testing or linking with gene-specific clinical trials in the future.
I put a couple of quotes here from an interview study that we did with people who had genetic counselling for dementia in their family just to show you what sometimes people say about genetic counselling. So, the first one said, "You know when you think to yourself, "Oh, maybe if I'd done this a bit different," but even understanding that something could be genetically predisposed, it shows there's nothing we could have done, so that sort of shows that it wasn't a choice. I don't know, but somehow, that made me feel better." And the second person said, "I also appreciate that we're told at the start that this isn't definitive, and even if nothing shows up now, things will be kept on a database. So that was really important for me too, knowing that even if we didn't get an answer today, maybe we might have an answer in 20 years." I put a few more quotes here about why people felt it was important in terms of leaving information for other relatives, because this can be a key motivation for coming to genetics, so these quotes are about leaving information for their family. And the last one is really mentioning that the conversations about genetics in families can be really difficult. And Vanessa says it's the elephant in the room and that she hadn't been able to talk to her siblings about it. So sometimes, genetic counselling can help with how to start those conversations.
The goals of genetic counselling are about helping the person with decision making about genetics, and whether or not genetic testing might be something that they want to do, to prepare for the sort of information that that can give, and taking into account things like uncertainty, worries, grief, feelings of guilt, and ways of coping with the possibility of a genetic cause for dementia. What the genetic information means to each person can be really different depending on their experiences and their outlook on life, their personal values. And talking about genetics with relatives can be difficult, so that is another key part of the appointments. To do this, genetic counsellors do have training in counselling theories and counselling models, and some of those are listed here. Narrative therapy is a key one, and as well as family systems theory, because we know it's really important for people to have a chance to tell a bit of their story, and about what dementia has meant for them and their family.
The foundations of genetic counselling are client-centred care, and integrating the information with the client's personal family and cultural values, as well as taking into account emotions, strengths and goals, alongside genetic information. So another couple of quotes here about why people went to genetics. The first person said, "Alzheimer's, I never thought that would happen to me, but I think it's important to go ahead and make sure that we're honest with our kids, and that they're involved in discussions, and also for me to feel peaceful about it, I guess." And the second said, "I feel safe, I feel educated. I feel like we, as a family, are respected in our decision." I should point out that coming to genetic counselling does not mean that you need to go ahead with any genetic testing. And a lot of people might decide not to, or put it on hold for a while, while they think about it more.
Genetic tests themselves are quite simple, so it's usually either a blood test or a saliva test. The results can take a few months. And depending on the clinic, they may be free or there might be a cost to that. Testing for the first person in a family looks through the letters of the DNA code of genes known to be linked with dementia, and it might or might not find a genetic cause. And if a clearer genetic answer is found, other relatives have the option of whether they would have a yes or no accurate test to find out about their future risk of dementia. Some common questions that people ask are whether they should get a test online, but we really caution against that because the quality and accuracy of online tests vary a lot. And a lot of those tests might say that they cover a lot of genes, but they may not cover dementia genes in the right amount of detail. So, we really recommend that you consult a qualified health professional.
Sometimes, people do have worries about whether it might impact insurance. And this is actually quite minimal in Australia in that health insurance is not affected in any way by genetic testing, which is good news. And for life and income insurance, the law changed in 2019 to protect people, in that life and income insurance companies can only ask if you're taking out quite a large policy. So, when a gene's already been found in the family, sometimes people are weighing up whether to have their own yes/no test to find out do I/don't I have that gene? Obviously, that brings up a lot of emotions, and it can be a really life-changing decision. So, we do follow international guidelines for at least two pretest appointments to happen before the test goes ahead. And that's really just about preparing as best as possible for getting that type of results, and it may not be just for the person themselves that the preparation could be useful, but also, sometimes, for partners or other people in their life.
And during that process, we try to link with any other support that might be helpful, if a person thinks a bit more support might be useful in preparing for results, then we definitely do that. And sometimes, people want to talk to others who have been in a similar situation, so it can be a lot to think about. We're really there to support people in making their own decisions. So aside from genetics, there are obviously other things that you can do to lower the risk of dementia, especially when that's relating to older age dementia when there may not be a clear genetic cause, but genetics may be part of the reason. Other things that can be part of why dementia might develop are things like hearing loss and brain health. So, things that people can do is to treat hearing loss in midlife, to keep physically and socially active, to avoid smoking and heavy alcohol intake if possible, and to treat things like high blood pressure and diabetes. So generally, looking after your health, it's a really positive thing to be able to do.
In summary, genetic counselling can provide information for families, and a lot of people see knowledge as power, and that might be why they've come to genetics. Sometimes, testing can help people to feel a bit more of a sense of control or reduced uncertainty, although genomic and genetic results can be really complicated, and sometimes, the results themselves are uncertain. They may be complicated to interpret, and that's where genetic counselling comes in and can be useful. If you do want to go to a genetics clinic and talk to a genetic counsellor, whether or not you're thinking about testing, you can still go to get the information and support, and usually, that's via referral from a GP. There are clinics throughout Australia and New Zealand, and there's a directory on the Human Genetic Society of Australasia website.
I'd like to thank you for listening, and also, thanks very much to Dementia Australia for the opportunity to talk today.
[Title card: No matter how you are impacted by dementia or who you are, we are here for you.]
[Title card: Dementia Australia. National Dementia Helpline 1800 100 500. Dementia.org.au]
[END of recorded material]
More for you
- Genetics and dementia
Find out how your genetic make-up affects your risk of developing dementia.
https://www.dementia.org.au/about-dementia/genetics-and-dementia - Testing and diagnosis
How to make the decision to talk to your doctor about changes in your memory, thinking, behaviour and mood, and what tests they might do.
https://www.dementia.org.au/about-dementia/dementia-testing-and-diagnosis - Frontotemporal dementia
Frontotemporal dementia is a condition affecting the brain’s frontal and temporal lobes. Learn about frontotemporal dementia and its symptoms, causes and treatment.
https://www.dementia.org.au/about-dementia/frontotemporal-dementia
- Human Genetics Society of Australia: Consumer Resources list
- Human Genetics Society of Australia: Definition of Genetic Counselling
- The Association for Frontotemporal Degeneration (USA): FTD and Genetics Overview
- National Institute on Ageing (USA): Alzheimer's Disease Genetics Fact Sheet
- Melbourne Genomics Health Alliance: Educational resources
The National Dementia Helpline
Free and confidential, the National Dementia Helpline, 1800 100 500, provides expert information, advice and support, 24 hours a day, seven days a week, 365 days a year. No issue too big, no question too small.