Testing For Familial Alzheimers Disease
The decision to undergo testing for FAD is very complex and the advantages and disadvantages must be carefully considered. The test does not produce a relative risk of acquiring the dementia, but is a definitive prediction of whether a person will get a profound and progressive illness in ones middle years. The test can only be completed with the informed consent of the person being tested. No one should ever be pressured to have such a test.
Knowing that you are carrying the gene may help some people plan for the future. It enables them to consider future lifestyle choices and to let their wishes be known to someone they trust. However, given that no cure is available an individual has to consider whether they want to know that they will develop dementia at some time in the future.
To help people consider these issues specialised genetic counselling is essential. The doctor can provide details of this service. In the future, when preventive treatments for Alzheimers disease become available, there may be increased reasons to seek testing.
As Part Of Our Livetalk Series Being Patient Spoke With Jessica Langbaum Co
Certain genes like ApoE that play an important role in the disease. ApoEs genetic variant, known as ApoE4, is the strongest genetic risk factor for developing Alzheimers in later life. Genetic tests by mail, like 23andMe and AncestryDNA, make it easy to learn about ones ApoE status and to learn that one may have a much higher likelihood of developing Alzheimers in their lifetime. But just because a person carries the ApoE4 variant doesnt mean that their fate is sealed: Alzheimers is a complicated disease, and genetics is one among many factors, from lifestyle and environmental factors to preexisting health conditions, that influence peoples risk.
Being Patient sat down with Jessica Langbaum, co-director of the Alzheimers Prevention Initiative at the Banner Alzheimers Institute, to discuss the complex role of genetics in Alzheimers, asking: Should people seek genetic testing for Alzheimers? And if they do, how can they ensure they are prepared for what they find?
How Is It Used
APOE genotyping is sometimes used as an added test to help in the diagnosis of probable late onset Alzheimer disease in symptomatic adults. However, the association of the e4 allele with late onset AD does not mean that it causes AD, only that more people with late onset AD have e4 alleles compared to similar aged peers without late onset AD. For this reason, APOE genotyping is referred to as susceptibility or risk factor testing since it indicates whether there is an increased risk of AD but is not specifically diagnostic of AD. For example, if a person has dementia, the presence of APOE e4 may increase the likelihood that the dementia is due to AD but does not prove that it is.
There are no clear-cut tests to diagnose Alzheimer disease during life. Healthcare practitioners can, however, make a reasonably accurate clinical diagnosis of AD by ruling out other potential causes of dementia and checking for a genetic predisposition to AD with APOE genotyping as supplemental information in conjunction with tau protein and beta amyloid testing.
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Genes: A Brief Background
The genes inherited from our parents and encoded in our DNA affect many aspects of our health. They guide the construction, operation, and repair of our bodies throughout life. Our parents have two alleles or versions of each gene, and we inherit one allele for each gene site from each of our parents. This is why siblings have unique characteristics unless they are identical twins.
Specific alleles that are passed down through a family can affect the likelihood of resisting or developing many diseases. Another way in which alleles may increase the likelihood of developing a disease is the occurrence of spontaneous changes in the structure of an allele, called a mutation. A small chemical change in an allele can have profound effects on a persons health. An altered gene may produce an altered protein that creates havoc in the body.
Discuss Test Results With A Doctor
Dont assume that the test results are equal to a diagnosis of any kind.
The SAGE test is a screening tool that helps doctors detect early signs of cognitive impairment that are typically not noticeable during a normal office visit.
When the test is repeated over time, doctors can watch for changes in cognitive ability. Being able to measure changes helps them detect and treat health conditions early.
Thats why its important to bring the completed test to the doctor to have it reviewed. If there are signs of cognitive impairment, they may recommend further testing.
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Genetic Testing For Alzheimer’s Disease
A blood test can identify which APOE alleles a person has, but results cannot predict who will or will not develop Alzheimer’s disease. Currently, APOE testing is used primarily in research settings to identify study participants who may have an increased risk of developing Alzheimer’s. This knowledge helps scientists look for early brain changes in participants and compare the effectiveness of possible treatments for people with different APOE profiles.
Genetic testing is also used by physicians to help diagnose early-onset Alzheimers disease and to test people with a strong family history of Alzheimers or a related brain disease.
Genetic testing for APOE or other genetic variants cannot determine an individuals likelihood of developing Alzheimers diseasejust which risk factor genes a person has. It is unlikely that genetic testing will ever be able to predict the disease with 100 percent accuracy, researchers believe, because too many other factors may influence its development and progression.
Some people learn their APOE status through consumer genetic testing or think about getting this kind of test. They may wish to consult a doctor or genetic counselor to better understand this type of test and their test results. General information about genetic testing can be found at:
Does The Parent Need To Know If They Have A Single
Some people may think that they have a single-gene change and want to use PGD to make sure that their child does not have it. However, they may want to avoid finding out whether they themselves have the changed gene. It is possible in some centres to use the technology without the parent finding out if they themselves have the change.
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Alzheimer’s Society’s View On Genetic Testing
What we think about genetic testing and how it relates to the needs of people affected by dementia.
Genes play a role in the development of many types of dementia, although the extent of this role varies between dementia types. A person with a parent or sibling with a dementia such as Alzheimers disease has on average a higher risk of developing the same condition themselves, although other factors such as lifestyle can also play a part.
At present, the relationship between genetics and dementia is not fully understood. We do know that a mutation in one of a small number of genes can cause someone to develop frontotemporal dementia or rarer, inherited forms of Alzheimers disease. These conditions both often start in people under the age of 65.
Predictive genetic testing is where the genes of someone who is related by birth to a person with diagnosed dementia are tested. The genetic test aims to see whether the relative has inherited the same mutation and so will go on to develop the dementia. At present such predictive genetic testing is only possible for inherited Alzheimer’s disease, in which very rare mutations in three genes are implicated, and frontotemporal dementia, which has known mutations in at least six genes. The most common form of Alzheimers disease affects about 520,000 people in the UK and most often starts in people over the age of 65. There are no approved predictive genetic tests for this form of the condition.
Genetic Testing For Alzheimer’s Has Emotional Risk
August 18, 2020 â Twelve years ago, Jamie Tyrone volunteered to participate in a clinical trial. The researchers wanted to know whether learning your genetic risk for developing some 20 or so different diseases, through a direct-to-consumer genetic test, would prompt you to take up a healthier lifestyle. But Tyrone wanted to get something else out of the study.
The San Diego-based retired nurse, now 59, had been living with mysterious progressive neurological problems for about 15 years. The debilitating weakness and fatigue had pushed her into early retirement. Sometimes she needed a scooter to get around the one-story ranch she and her husband bought to accommodate her increasing physical challenges. But doctors had never made a definitive diagnosis. While brain scans ruled out multiple sclerosis, this clinical trial would tell her if she had a gene that predisposed her to the condition.
So focused on learning her genetic risk for MS, Tyrone didnât give any thought to the other diseases sheâd learn her risk for, including Alzheimerâs disease.
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Blood Tests Available Now
A blood test is available now, through your doctor, that delivers a result in about 10 days and accurately determines whether someone has Alzheimers disease. The Preclivity AD Test from C2N Diagnostics measures proteins in blood plasma that indicate a buildup of plaques known to cause dementia in peoples brains.
Cost
The cost of this Alzheimers blood test is $1,250, less expensive than a PET scan that looks for the same protein buildups. Unfortunately, the price tag cannot be covered by Medicare or Medicaid, but C2N says people who cant afford the test can qualify for a discount based on their income.
Does it Work?
C2N Diagnostics says they tested Preclivity AD in 686 people and compared it to the results of PET scans. When PET scans showed a high amount of amyloid-beta, a protein that turns to plaques and tangles in the brains of people with Alzheimers, the blood test agreed 92 percent of the time. When the PET scan showed no amyloid, the blood test showed the same about 77 percent of the time.
How to Get the Blood Test
The Preclivity AD Test has not been approved by the Food and Drug Administration. It is currently available only through a doctor, and can be sold by the company under rules for commercial laboratories. The test, in other words, is available despite lacking FDA approval, though C2N has said the FDA is planning on reviewing the test in 2021. The Alzheimers Association says it wont endorse the test until there is FDA approval.
Is There Anything You Can Do
Unlike glaucoma, diabetes, or some cancers, there is no early detection screening for Alzheimerâs disease. Thereâs no definitive way to prevent it either.
âThereâs just nothing practical or actionable to do with this information,â Weissman says. âItâs not going to change anyoneâs medical management.â
The lifestyle recommendations that might help lower risk for Alzheimerâs, Weissman explains, are the things that doctors encourage their patients to do anyway. Research shows that a healthy diet, plenty of exercise, enough sleep, fewer calories per day or periodic fasting, and brain stimulation can all improve your odds of living out your life dementia-free.
But, 23andMeâs Wu argues, âWe know these are standard recommendations for staying healthy, but we also know that most people donât follow them. Genetic information can be the triggering event that gets people motivated.â
It certainly motivated Julie Gregory of Long Beach, IN, to overhaul her lifestyle. Like Tyrone, she took a genetic test for reasons unrelated to her Alzheimerâs risk. When her 23andMe results revealed that she had two copies of APOEe4, she thought of those âsenior momentsâ sheâd had since she was 49. Sheâd forget the names of people sheâd known for 20 years when she ran into them at the grocery store. Her test results filled her with dread. Were the wheels already in motion on the road to Alzheimerâs disease?
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Symptoms Of Alzheimers Disease
- Memory loss Repeating things, often forgetting conversations or appointments, routinely misplacing things, eventually forgetting the names of family members and everyday objects.
- Problems with abstract thinking People with Alzheimers may have trouble recognising and dealing with numbers.
- Difficulty finding the right word It may be a challenge for those with Alzheimers to find the right words to express thoughts or even follow conversations. Eventually, reading and writing also are affected.
- Disorientation People with Alzheimers disease often lose their sense of time and dates, and may find themselves lost in familiar surroundings.
- Loss of judgment Solving everyday problems, such as knowing what to do if food in the oven is burning, becomes increasingly difficult, eventually impossible. Alzheimers is characterized by greater difficulty in doing things that require planning, decision making and judgment.
- Difficulty performing familiar tasks Once-routine tasks that require sequential steps, such as cooking, become a struggle as the disease progresses. Eventually, people with advanced Alzheimers may forget how to do even the most basic things.
- Changes in Personality
What Role Do Our Genes Play In Dementia
As dementia is so common, many of us will have a relative living with the condition but this does not mean we will develop it too.
Dementia is caused by diseases that affect the brain, such as Alzheimers disease. The likelihood of developing dementia will usually depend on a complex mix of factors like our age, medical history and lifestyle, as well as our genes. Most cases of dementia are not directly caused by genes we inherit from our parents.
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What Are The Benefits Of Predictive Testing
Having the test can be helpful for the following reasons:
- It can remove the anxiety of not knowing especially as the person approaches the age at which any symptoms of dementia are likely to start.
- It can give the person the option of entering into a clinical trial.
- It can help with family planning.
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 Alzheimers disease and is concerned that it may be familial, they should gather as much information as they can about their relatives family history. Useful information would include how old family members were when they died, whether they had dementia and, if so, whether Alzheimers 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 an individual as clearly as possible, so that they may make an informed decision about whether to proceed with genetic testing. Both the individual 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 an individual 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:
For more information on genetic counselling and testing please visit our FAQs section. For more information on genetic testing and dementia, you may find the Alzheimers Society website useful.
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When Is Genetic Testing For Dementia Appropriate
In some cases, it may seem likely that a persons dementia is caused by a single-gene change for example, if the person has a very strong family history of dementia. In these cases, it may be appropriate to offer genetic testing to the person and to their family.
However in most families dementia will not be caused by a single-gene change. In these cases, genetic testing will not be appropriate. This is because testing for risk variants does not provide any certainty about the persons chances of developing dementia.
I Think I Am At Risk Of Fad What Next
This page is here to guide you on what to do if you think you or your family may be at risk of familial Alzheimers disease .
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, we have provided some information that you may find helpful.
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Dementia And Down Syndrome
People with Down syndrome are born with an extra piece of DNA. This means they also have an extra copy of the APP gene. This leads to the build-up of amyloid plaques in the brain, which play a role in the development of Alzheimers disease. While not everyone with Down syndrome will go on to develop symptoms of Alzheimers, most people with the condition over the age of 40 will have amyloid build-up. It is estimated that about 50% of people with Down syndrome develop symptoms like memory loss, usually in their 50s and 60s.
To find out more about Down syndrome and dementia you can contact Downs Syndrome Association helpline on 0333 1212 300 or visit their website www.downs-syndrome.org.uk.
Getting A Genetic Test For Familial Alzheimers Disease At 25
This blog is a cross-post with The Huffington Post.
When people hear the word Alzheimers, many envision an elderly person shut away in the depths of a care home. As a 25-year-old, I was all too aware that young people assume that its a natural part of ageing, and nothing for them to worry about yet. But its not, its a brain disease that strips everything away from the individual and it doesnt just affect the elderly.
For an unfortunate few of us its something that will have a huge impact on our lives, from the second were born to the moment we die.
Around the world there are only a few hundred families who have been identified as having a rare, inherited form of the disease. Familial Alzheimers accounts for less than one percent of Alzheimers disease cases, and usually takes effect before the age of 65. For some, it is as young as 30.
My dad started showing the symptoms of Alzheimers when he was just 41, and I was just 11. His dad, grandmother, and dads cousin had already died from the disease, and his younger sister soon got it too. There is now a young generation of our family waking up to the reality that well be next.
Ian Fleig & daughter Jess at the London DIAD Family Conference.
You often hear people talk about life-changing experiences but I dont think Ill ever enter a room again knowing that the next few words spoken will truly change everything.
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