Familial Alzheimer’s disease (FAD) is an inherited form of Alzheimer’s disease. It is caused by a genetic fault that runs within families. It accounts for less than 1% of Alzheimer’s disease cases overall.
If you or someone you know has been affected by FAD, or you are interested in learning more, then RDS can provide you with information and advice.
Understanding FAD
Unlike typical Alzheimer’s disease (the non-inherited form) which usually occurs in people in their 70s or 80s, FAD usually occurs much earlier. People with FAD typically first develop symptoms before the age of 65, most commonly in their 40s or 50s. However, this varies considerably between different families. In some families, individuals may be as young as their early 30s when they become affected.
The initial symptoms of FAD are usually similar to those of typical Alzheimer’s disease – primarily memory loss. The memory problems in Alzheimer’s disease are different from everyday forgetfulness. Importantly, they are ‘progressive’, meaning that they become worse over time. They are also different in that in FAD, other people are usually more aware of the memory problems than the person experiencing them. Over time, the memory problems in Alzheimer’s disease spread to affect other forms of thinking such as new difficulties with planning or performing calculations. Symptoms can be hard to detect, but a clear sign is a distinctive and progressive decline in abilities.
It is important to note that many people in families with FAD worry about their memory – and understandably so – but most of the time this is not an indication that they have developed FAD.
Sometimes FAD is referred to as autosomal dominant Alzheimer’s disease (ADAD). This is a different name to describe the same condition.
Causes
Familial Alzheimer’s disease (FAD) is a rare form of Alzheimer’s disease caused by faults (known as mutations) in genes that run within families. Mutations in three genes are known to cause most cases of FAD. These are the presenilin 1 (PSEN1), presenilin 2 (PSEN2) and amyloid precursor protein (APP) genes. A mutation in PSEN1 is the most common of these three to cause FAD.
To date, over 200 different mutations have been found in the PSEN1 gene, over 50 in APP and less than 20 in PSEN2. There are mutations that affect many different families and some that may only affect one family (to our knowledge). However, more mutations continue to be discovered.
In each family the disease is caused by a mutation in a single gene and so a single copy of the mutated gene, inherited from one parent, will cause the disease. The onset of symptoms in FAD occurs usually at a relatively young age, usually 30s, 40s, or 50s and other family members may also have been affected at a similarly young age.The symptoms and disease progression rate vary significantly between mutations and within the same mutation, and even within the same family.
The age at which people develop symptoms varies considerably between different families, but in some families, individuals may be as young as their early 30’s when they become affected. Within a single family, people tend to develop the disease at broadly similar ages. The symptoms and disease progression rate vary significantly between mutations and within the same mutation, and even within the same family.
The age of symptom onset – when a person starts showing symptoms of FAD – often depends on the genetic mutation. Studies suggest that people with the PSEN1 mutation have symptom onset at an younger age, compared to APP mutation carriers. However the age of symptom onset varies a lot between different PSEN1 mutations. The oldest ages of symptom onset is mostly seen in people with PSEN2 mutations, which are rarer than APP mutations or PSEN1 mutations. PSEN1 mutations are the most common cause of FAD.
Most commonly Alzheimer’s disease (AD) is not familial and is not caused by a genetic mutation. In most cases, the relatives of someone who has Alzheimer’s disease have no greater risk of getting Alzheimer’s disease than anyone else. This is a very different situation to what occurs in FAD, where the disease is entirely caused by inheriting a faulty gene.
Diagnosis and testing
How likely am I to inherit FAD?
If someone has one of the gene mutations that cause FAD, then each of their children has a 50% chance (1 in 2 chance) of inheriting the faulty gene. Each sibling of someone with the faulty gene will have had a 50% chance of inheriting it.
An affected parent could have all children affected or unaffected, or a mixture of both. FAD affects males and females equally and does not skip generations. However, it may appear to skip a generation if a person with the faulty gene dies of another cause before symptoms develop.
People with familial Alzheimer’s disease usually have a strong family history of the illness, which means that, as well as one of their parents, they know of cousins, aunts/uncles and grandparents who were affected at a similar age and who belong to the side of the family of their affected parent. In some cases, an individual may not know whether they have a family history of Alzheimer’s disease, for example if they do not know their biological parents or if their parents died young.
As far as we know, if a person is tested and has inherited one of these faulty genes, then they will almost certainly go on to develop Alzheimer’s disease at some point in their life. They are also highly likely to develop symptoms around the same age that their parent developed them. This means if a person is a lot older than an affected parent and does not have problems then they are unlikely to have inherited the genetic mutation and their children are not at risk.
The genetic mutations that cause familial Alzheimer’s disease are not responsible for all of a persons other characteristics, such as how you look, your height or your personality. Therefore, there is no evidence to suggest that those who look most like the person with the mutation are more likely to inherit the mutation.
Genetic testing and counselling
If someone has a relative with Alzheimer’s disease and is concerned about whether it may be familial, they should gather as much information as they can about their relative’s family history so that they can discuss it with the doctor caring for their relative. The doctor will also be able to refer them to a specialist genetic counselling service if appropriate to discuss their concerns and arrange genetic testing if needed.
The results of any genetic test have important implications not only for the person being tested but also for the rest of the family. It is important to discuss these carefully with a specialist who has expertise in genetic counselling, before any genetic tests are performed.
A genetic test for FAD can be performed on a blood sample and is usually done because several other family members have Alzheimer’s disease. However, it may also be performed when symptoms or brain scans suggest familial Alzheimer’s disease. For more information on the different types of genetic testing and counselling for FAD, please see the information provided in the ‘I think I am at risk of FAD. What next?’ section of this page. Further information is also available on our Genetics and Risk page.
It is important that healthcare professionals are better informed about FAD and equipped to recognise the symptoms. Rare Dementia Support is working to improve awareness of FAD and other rare dementias and to train healthcare professionals. For more information and resources visit our Learning page. By increasing awareness and understanding of FAD, we hope to ensure that healthcare professionals and communities are better equipped to support people affected by a diagnosis of FAD. Help us by sharing your stories and contacting us at contact@raredementiasupport.org
See the RDS website page on getting or refining a diagnosis for more information.
You can find out more about genes and typical Alzheimer’s disease by visiting the Alzheimer’s Research UK website. One of our members has shared their journey of undergoing genetic counselling and testing for FAD. You can read Jess’ story here.
I think I am at risk of FAD. What next?
When living at risk of FAD, people naturally ask what will happen next. Will I inherit this condition from my parents, and can I pass it on to my children? Should I get tested? What support is available to me?
If you think you are at risk of FAD, the following information may be helpful.
Genetic testing and counselling
In families where a gene mutation is known or suspected, expert genetic advice is important.
If someone has a relative with Alzheimer’s disease and is concerned that it may be familial, they should gather as much information as they can about their relative’s family history. Useful information would include how old family members were when they died, whether they had dementia and, if so, whether Alzheimer’s disease was the cause, and the age at which they developed symptoms.
The doctor caring for their relative will be able to refer them to a specialist genetics or neurogenetics clinic to discuss their concerns and arrange genetic counselling and testing if needed.
Genetic counselling is not psychological counselling. It is the process of a specialist explaining all of the facts and options to a person as clearly as possible, so that they may make an informed decision about whether to proceed with genetic testing, while assessing a person’s readiness in receiving this information. Both the person at risk and their next of kin should be involved in these discussions as a diagnosis of FAD has implications for the whole family.
If a person decides after genetic counselling to get a genetic test, then a blood test is carried out to look for a faulty gene that can cause FAD. There are two types of testing:
- Diagnostic genetic testing is typically offered when someone has developed symptoms of Alzheimer’s disease at a young age and has a strong family history of the condition. It may also be offered to people who have symptoms of Alzheimer’s disease under the age of 65, but whose family history is not known.
- Predictive genetic testing: If the precise FAD mutation affecting a person is known, it is possible for that person’s adult children and siblings to undergo genetic testing in order to find out whether they have inherited the mutation. This type of testing is done on people who are currently well and have no symptoms of Alzheimer’s disease.
For more information on genetic testing and dementia, you may find the Genetic Alliance website and Alzheimer’s Society useful.
If I have the gene mutation, what can I do to avoid passing the gene onto my children?
It is possible to prevent children from inheriting the mutation by undergoing pre-implantation genetic testing – known as PGT. The Human Fertility and Embryology Authority (HFEA) have granted a licence allowing testing for mutations for couples who wish to pursue PGT.
PGT is available to couples if there is a specific genetic mutation known to run in the family, although the person undergoing PGT does not necessarily need to find out whether they carry the mutation themselves. It is a lengthy and complex process involving assisted reproductive technology, more commonly known as IVF (in vitro fertilisation). The chances of success depend on various factors and there are a number of criteria that must be fulfilled if a couple is to be considered for PGT. At present, the NHS only covers the costs of one child per couple. More information on PGT is available on the Human Fertilisation and Embryology Authority website.
We are aware that making decisions about pre-implantation genetic diagnosis is significant and complex, and we recognise and empathise with the emotional challenges as well as physiological challenges it poses for people considering it as an option.
Symptoms of FAD
The early symptoms of familial Alzheimer’s disease (FAD) vary from person to person but are usually similar to those of typical Alzheimer’s disease – primarily memory loss. Most people with FAD have difficulties with memory, for example with recalling events and learning new information, in the early stages of their condition.
It is important to note that these symptoms are different from everyday forgetfulness as they are ‘progressive’, meaning that they become worse over time. In the early stages of FAD, symptoms may be hard to detect.
For some people living with FAD, memory impairment remains the only problem for many years. However, more unusual symptoms and signs may also occur. These can include:
Cognitive symptoms:
- language difficulties, such as word-finding and understanding speech and writing
- problems with coordinating movements, for example when getting dressed
- changes in behaviour and personality that are uncharacteristic
- a lack of awareness about their condition and what is happening around them
Neurological symptoms:
Physical symptoms
- difficulties with physical movement; an individual may experience trouble walking due to stiffness in the legs, unsteadiness and slow or involuntary jerking movements
- difficulties with eating
Psychiatric symptoms:
- delusions – believing things that are untrue (having delusions)
- hallucinations – seeing or hearing things that are not really there
- anxiety and agitation
- depression or apathy
- sleep-wake reversal – when individuals are awake a lot at night and are sleepy in the day
These more unusual symptoms may develop in the later stages of FAD, but in some cases, they can happen in the early stages. In some people, they may be the very first symptoms of the disease, occurring before any problems with memory. There are medications that can be prescribed to help manage some of these symptoms. More information is available in the treatment section below, and also here.
The length of time a person survives after they first develop symptoms of FAD varies widely. At present, there is no accurate way to predict how long a person with FAD will survive. Longitudinal research studies are working to understand this by following individuals as their condition progresses.
Familial Alzheimer’s disease, like typical Alzheimer’s disease, is a progressive condition, meaning symptoms will get worse over time. In the mid to later stages, a wider range of symptoms usually develops. Problems with memory loss, language, reasoning and orientation typically progress to the point at which full-time care may be required. For advice on strategies to help manage some of these symptoms please visit the managing and adapting page, where there is lots of helpful advice, as well as a specific section for FAD at the bottom.
Families affected by FAD may find coming along to our FAD Support Group meeting helpful, which is held annually. This meeting provides an opportunity to speak to others who are in similar situations, as well as address your questions and concerns with a wide range of professionals in a space of mutual respect and understanding. We also facilitate a range of other support options.
If you would like to talk to somebody about how the issues raised here have affected you, please get in touch.
Living with FAD
Support
Receiving a diagnosis of FAD can be isolating and can have an impact on not only the person living with the diagnosis, but also family members, friends and carers. It is important that the right support is available, not only for the person with FAD, but also for the people who care about and support them. The RDS support group meetings can be a good place to start.
Support groups are a great way of accessing help, information, advice and support in a space of mutual respect and understanding. They provide opportunities to speak to professionals and ask questions, as well as for connecting with others in similar situations.
People living with FAD and their friends and family are welcome to join our London support group meetings, our virtual small group meetings or to see what Regional Network Hubs might be available. Additional bespoke support is facilitated by RDS for people affected by or living with FAD.
Because FAD is rare, many healthcare services may not have much experience in supporting people affected by it. However, it can be helpful to seek support from a variety of health and social care professionals such as GPs and nurses, community mental health teams and social workers. Some people with FAD may experience problems with movement or coordination. In these cases, support from a neurologist, physiotherapist or occupational therapist should be accessed. See the RDS website page on professionals for more information about what types of allied health professional support is available.
As FAD is rare and the symptoms can vary from person to person, it may be hard for people with FAD to receive the correct diagnosis. This can be frustrating and distressing. By increasing awareness and understanding of FAD, we hope to ensure that healthcare professionals and communities are better equipped to support people affected by a diagnosis of FAD. Help us by sharing your stories and contacting us at contact@raredementiasupport.org, and visit our Support at different stages page for more information.
Research
Some RDS members living with FAD find that contributing to research is a beneficial way of making a difference, if not for themselves, then for others who will receive this diagnosis in the future. You can read more about getting involved on our research opportunities page, or take a look at our FAD specific research project currently underway.
Strategies for managing and adapting to FAD
The symptoms and challenges associated with FAD have some similarities with Alzheimer’s disease. Therefore, some of the same strategies for managing them can also be employed. There are a variety of strategies that people have found useful to help them adapt to and manage the symptoms of FAD. Everyone’s experience of FAD is unique to them, and what works for some may not work for others.
You may find our managing and adapting page helpful, and we also have a specific section at the bottom of the page about adapting emotionally with familial forms of dementia. The Alzheimer’s Society also provides relevant and helpful information.
Treatment
Unfortunately, at the moment there are no medications that can prevent familial Alzheimer’s disease (FAD). There is a great deal of ongoing research in an effort to find treatments that alter or slow the course of FAD, or to prevent it starting in the first place. If you would like to know more about how you can get involved in clinical trials for FAD, please visit the Dementia Research Centre website.
Medications like cholinesterase inhibitors or memantine that are used to stabilise or improve memory-related symptoms in typical Alzheimer’s disease, are also used for FAD. However, they do not slow down the underlying progression of the disease in the brain. This means that over time symptoms will worsen.
Medication for behavioural symptoms and mood changes may become useful as FAD progresses. There is some evidence that selective serotonin reuptake inhibitors (SSRIs) may help improve behavioural symptoms. For example drugs such as sertraline or citalopram.
Other medications may also be helpful for treating specific symptoms in FAD if they are present, including those available for physical difficulties such as involuntary jerking movements, seizures or leg stiffness.
Symptoms of depression and anxiety are relatively common in FAD and may be helped by medication. It is important to treat these symptoms if they are present, as they may exacerbate a person’s memory impairment. Psychological therapy may also be helpful if a person is in the relatively mild stage of the disease.
It is not uncommon for the relatives of people with familial Alzheimer’s disease to experience anxiety about their risk of developing the disease. Everybody has small memory lapses from time to time, but these may cause heightened anxiety in someone from a family affected by familial Alzheimer’s disease. Unfortunately, feeling anxious and low in mood can itself have an adverse effect on memory. It is therefore important that people at risk of familial Alzheimer’s disease seek help if they experience significant anxiety or depression; counselling, psychological therapy or medication may all have a role to play in improving things for them.
Please note that you should always speak to your GP or healthcare professional before taking any medical treatment.
For information about general drug treatments for dementia look at our Drug treatments page or take a look at this Alzheimer’s Research UK news page.
Talking about your diagnosis
Knowing when and how to tell family, friends and colleagues about a diagnosis of FAD can be difficult. It can take time for people to understand and come to terms with a condition they have never heard of before. There is no right or wrong time to tell those around us, and people often have a sense of the time that feels right for them.
It could be helpful to talk this through with members of the RDS FAD Support Group who have been in a similar situation, and who have direct experience of discussing their concerns with those closest to them. Please get in touch using the contact@raredementia.org email address for more information about the specific FAD support we can offer. Many members find it helpful to share their story with other people living with a rare dementia diagnosis, and there are a range of opportunities for this at the small and large group meetings we offer.
Finding the right language is also important when talking to people about a diagnosis. We have made a short film, featuring the experiences of people living with FAD and their families as well as the professionals working with them. Visit our Adapting emotionally page for more advice about talking about your diagnosis.
Support for children
Unlike many other dementias, FAD often affects people in middle age or even younger, meaning that it is likely there will still be children at home. When any parent faces a serious illness, their children need support in coping with and understanding their parent’s condition.
As there is an inheritance risk associated with FAD, children of parents living with FAD will also have additional psychological and emotional challenges that will require support.
In order to help children manage and understand how FAD may affect them and their parent, it is important to try and allow for open conversation and questions as much as possible. Without factual information, children may often fill the gaps in their knowledge with incorrect facts. It is therefore very important to facilitate conversation, provide information and allow for emotions and feelings to be discussed.
There are several links which provide helpful information on discussing FAD with young people. The links are not all FAD-specific, but provide information that is transferrable and relevant:
- Support for children and young people affected by dementia
- Carers Trust: Young Carers
- Information for Young Carers from the NHS
- Alzheimer’s Association: Living with Alzheimer’s – just for kids and teens
- Young Dementia UK
There is also a need to address the young person’s understanding of whether they might inherit the FAD gene mutation, in an age sensitive and appropriate manner. Predictive testing is usually only done in people over 18. However if a person younger than 18 wants to talk about testing, they can be referred to a clinical geneticist who will go through the issues and concerns that the young person has. It is important that a young person is supported in their request and not just told that they can’t be tested until 18.
The information on our Adapting emotionally page may also be helpful. It could be helpful to talk this through with members of our FAD Support Group who have been in a similar situation. Please use the contact@raredementiasupport.org email address to get in touch for more information about the FAD specific support we can offer.
Latest FAD seminar
You can view the latest FAD seminar, which features a full recording of the meeting, including research updates, clinical presentations, member stories, and a Q&A session.
Latest FAD stories
The woman who discovered FAD
A spotlight on Carol Jennings: Pioneer in the discovery of an Alzheimer’s disease gene.
FAD
Living at risk of FAD: Jess’ story
Jess Fleig Talks about why she chose to get a genetic test for FAD at 25.
FAD
Living with FAD: A short film
People living with FAD, their families and professionals share stories, insights and advice.
FAD