What Are The Claims About Genetic Testing Kits
There have been some stories in the news about buying kits that can tell you about your genetic makeup. These kits include testing for genes that can influence your risk of developing certain conditions, including Alzheimer’s disease.
However, the genetics behind Alzheimer’s disease and other forms of dementia is complex and these kits cannot tell the complete story about a person’s risk of developing the condition.
Chris Hemsworth Discovers He Has Rare Genetic Makeup That Significantly Increases Risk Of Alzheimer’s Disease: My Biggest Fear
Chris Hemsworth’s new show with National Geographic on Disney Plus is “a mission to live better for longer.” But because of that show, he has come face-to-face with his “biggest fear” that he might develop Alzheimer’s disease.
During one episode of the show, the 39-year-old “Thor” actor underwent genetic testing to learn more about his present and future health. It turns out that Hemsworth has a rare genetic makeup with two copies of the APO4 gene, which has been connected to an increased risk of Alzheimer’s disease.
“ApoE4 is the strongest risk factor gene for Alzheimer’s disease,” a 2021 study by the National Institutes of Health says, “although inheriting ApoE4 does not mean a person will definitely develop the disease.”
While about 25% of the population has one copy of the gene, only 2% to 3% have two, according to that research.
“The idea that I won’t be able to remember the life I’ve experienced or my wife, my kids, this is probably my biggest fear,” Hemsworth says in the show’s fifth episode.
During filming, the show’s longevity doctor Peter Attia first told Hemsworth about the finding off-camera, Hemsworth told Vanity Fair. That conversation, Hemsworth said, “was pretty shocking.”
It’s also a disease that his family has significant experience with. Hemsworth’s grandfather has Alzheimer’s.
He also told Vanity Fair that there are some days when his grandfather is “quite joyful and gives you a big hug.”
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.
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Path To Preserving Brain Health
While Hemsworth is met with the life-altering news in the show, a doctor in one clip points out that the learned information is a blessing and can help motivate Hemsworth to look after his brain health.
“It’s my belief that if we take every step possible, we can reduce your risk to that of anyone else,” Attia tells Hemsworth in a clip.
There is currently no cure for Alzheimer’s disease, but the Centers for Disease Control and Prevention says there are ways to reducing the risk of Alzheimer’s, including regular exercise, managing blood sugar and maintaining a healthy weight. Other ways that the CDC says Alzheimer’s can be prevented include quitting smoking, avoiding excessive drinking and getting enough sleep.
“It very quickly just became another wonderful motivation to make some changes and arm myself with all the tools to live a healthier, better life,” Hemsworth said while appearing on “Good Morning America.”
He continued, “I think any of the motivations for living better can come in many shapes and forms and this was, you know, whatever I’m going to do now to benefit and protect myself from brain health will benefit every aspect of my health and well-being.”
“Limitless” is now available to stream on Disney+.
Disney is the parent company of ABC News and “Good Morning America.”
Chris Hemsworth Discovers He May Be At Risk For Alzheimers Disease In New Series Limitless
The “Thor” star shares what he fears most about the disease.
Chris Hemsworth is opening up about eye-opening news he learned about while filming his new series, “Limitless.”
The “Thor” star, who puts his physical and mental strength to the ultimate test in the National Geographic show airing on Disney+, is sharing that he may have a higher risk of developing Alzheimer’s than the general population after undergoing extensive bloodwork.
In a clip from the episode on brain health, Hemsworth takes a genetic test and meets with longevity specialist Dr. Peter Attia who tells the actor that he has two copies of APOE4, or the apolipoprotein E gene, which is the strongest risk factor gene for Alzheimer’s disease, according to the National Institute of Aging.
However, genetic testing for Alzheimer’s is in its early days, and not recommended for everyone.
In fact, the National Institute of Aging cautions against genetic testing for most people because a positive test doesn’t necessarily mean that you will develop Alzheimer’s and can cause undue stress and anxiety. But Dr. Attia points out that for anyone — no matter their genetics — making healthy choices can help reduce the risk of Alzheimer’s later in life.
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How Will Genetic Testing Help You And Your Patient
In the case of genetic testing for early-onset familial AD, a positive test result for a known family gene mutation can result in:
- Relief from uncertainty
- An increased feeling of control
- Opportunity to plan life decisions
A negative test result for a known family gene mutation for early-onset familial AD can result in:
- Relief from fear of developing early-onset AD
- Knowledge that children are not at risk for early-onset AD
Genetic Research For Alzheimers Disease
Researchers think there are probably many more genes that affect the risk of Alzheimerâs. Discovery of these genes will help doctors:
- Understand the disease better and learn why it affects certain people in certain ways
- Learn more about what increases your risk of getting it
- Identify people who are at higher risk so they can home in on preventive care
- Develop new treatments
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My Father Has Been Diagnosed With Probable Late Onset Alzheimer Disease And His Apoe Genotype Test Is Negative For E4 Alleles Should His Doctor Be Doing Other Genetic Testing
No, not at this time. Forty percent of individuals who have late onset Alzheimer disease are negative for APOE e4 alleles.
Currently, there are only three known genes that are associated with AD. Mutations in each of these genes are associated only with a rare and early onset form of AD. Changes to these genes are not associated with typical or late onset AD. If you have a strong family history of AD that includes multiple family members across several generations, you may want to talk to your doctor about genetic counseling for risk assessment.
Most Cases Of Alzheimers Are Not Caused By A Single Gene
The good news is that most cases of Alzheimers disease are not passed along by a single gene. Among the millions of people in the world affected by AD, those known to have developed the disease due to the inheritance of a single gene account for a very small percentage.
The bad news is that even without inheriting one of the genes that are known to transmit AD, the disease is still a significant health risk for any older adult.
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Dont Order Apoe Genetic Testing As A Predictive Test For Alzheimer Disease
APOE is a susceptibility gene for later-onset Alzheimer disease , the most common cause of dementia. The presence of an 4 allele is neither necessary nor sufficient to cause AD. The relative risk conferred by the 4 allele is confounded by the presence of other risk alleles, gender, environment and possibly ethnicity. APOE genotyping for AD risk prediction has limited clinical utility and poor predictive value.
The items on the ACMG list are provided solely for informational purposes and are not intended as a substitute for consultation with a medical professional. In determining the propriety of any specific procedure or test, patients should consult with their individual providers and providers should apply their own professional judgment to the specific clinical circumstances presented by each individual patient.
Why I Dont Want To Know My Genetic Risk For Alzheimers Disease
I have studied brain health and risk reduction for Alzheimers disease and related dementias for more than ten years. While there is no disease-modifying therapy available on the market today, there is emerging evidence that many common-sense lifestyle choices can improve the resilience of our brains and decrease our risk of developing dementia.
In 2017, the Lancet Commission released a growing body of evidence suggesting that nine risk factors could be modified to help delay or prevent dementia: less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes and low social engagement. In 2020, the Commission added three more modifiable risk factors to its list to make a total of twelve, accounting for around 40 percent of worldwide dementias.
My father and his three siblings all had late-onset Alzheimers disease. It is a cruel, mind-robbing disease, and I wish it upon no one. This is why in 2020 I launched the Milken Institute Alliance to Improve Dementia Care, a cross-sector collaborative that includes more than 60 leaders across eight stakeholder groups: advocacy, research, health systems, industry, philanthropy, government, community-based organizations and people living with dementia and their caregivers.
Im not sure what I would do differently if I knew I had the APOE e4 gene, so I choose not to be tested.
Reducing Risk Already
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What Does The Test Result Mean
People who have symptoms of Alzheimer disease and have one or more APOE e4 copies are more likely to have AD. However, it is not diagnostic of AD and should not be used to screen asymptomatic people or their family members. Many individuals who have APOE e4 alleles will never develop AD. Even in symptomatic people, only about 60% of those with late onset AD will have APOE e4 alleles.
Although APOE genotyping may be used clinically by Alzheimer experts, it can only provide additional information about a person with dementia. A definite diagnosis of Alzheimer disease can only be made by examining a persons brain tissue after their death.
Effects On Blood Brain Barrier
APOE4 can also increase blood-brain barrier permeability with respect to APOE3 in an A-independent manner, as shown in APOE4 versus APOE3 knock-in mice77 and confirmed with dynamic contrast-enhanced MRI in the medial temporal lobe of cognitively healthy and mildly impaired APOE4 carriers versus APOE3 homozygotes24. The underlying proposed mechanisms include the activation of cyclophilin A, resulting in increased levels of MMP9 and pericyte injury78, and disruption of the capillary basement membrane 77.
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Whos A Good Candidate
ApoE4 genotyping is not regularly used by most neurologists,Dr. Sabbagh says, and advisory groups recommend that people who do not havesymptoms not get tested.
But he does believe that the test can be used safely and without causing harm or distress in some people.
To me, people who are appropriate candidates are people with mild cognitive impairment, Dr. Sabbagh says. These are likely adults between the ages of about 50 and 75 who demonstrate early symptoms of Alzheimers disease and have already gone through a family history and neuropsychological testing with a neurologist.
I do order it to answer the question why not just what, he explains. Some people want to know why they got Alzheimers disease, so this can help explain that they inherited it and were born with the risk.
Genetic Marker Associated With Risk Of Alzheimers And Heart Disease
Variants in the ApoE gene are associated with the risk of Alzheimers disease and cardiovascular disease. This cheek swab test determines which of the E2, E3, or E4 variants of ApoE you have, thereby assessing your level of genetic risk.
Apolipoprotein E is an important regulator of cholesterol and triglyceride levels in your blood and supports lipid transport and injury repair in your brain.1
Alzheimer’s disease is a progressive disease associated with the aggregation of proteins called amyloidß and tau, which deposit in AD brains as plaques and tangles. These plaques and tangles injure synapses in your brain and ultimately cause neurodegeneration and dementia.2,3
AD usually occurs later in life and is referred to as late-onset AD . Although multiple genetic and environmental risk factors are involved in LOAD, impairment in Aß clearance by ApoE is a major contributor to development of the disease.4
There are three different forms of the ApoE gene known as E2, E3 and E4 alleles. Genetically, E4 is the strongest risk factor for developing LOAD.5-7 According to the National Institute of Health, inheriting a single copy of ApoE4 from a parent increases the risk of Alzheimer’s disease by about three-fold. Inheriting two copies, one from each parent, increases the risk by about 12-fold.8 In fact almost 40% of AD patients have inherited an E4 allele.9
Instructions
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References
Recommended Reading: How Many People Will Get Dementia
When Is It Ordered
APOE genotyping may sometimes be ordered when an individual has symptoms of progressive dementia, such as:
- Loss of memory that affects daily lifeforgetting information that was recently learned. This can occur with normal aging, but the information is usually remembered later. This includes forgetting important dates or events, having to rely on memory aids, and asking for the same information again and again.
- Difficulty planning or problem solving, such as keeping track of bills and payments
- Problems completing usual tasks, such as forgetting how to get to a familiar location
- Confusion about place or timelosing track of time, forgetting where you are or how you got there
- Increasing difficulty reading or judging distances
- Problems speaking or writingforgetting words, repeating the same thing, struggling with vocabulary
- Losing things more frequently and not being able to logically retrace steps to find them
- Impaired judgment, such as giving away unusually large amounts of money
- Increasing withdrawal from activities, including social, work or family events
- Changes in mood and personality, such as increasing anxiety, fear, suspicion and depression
After non-AD causes, such as overmedication, vascular dementia , and thyroid disease, have been ruled out, APOE genotyping may help determine the probability that dementia is due to Alzheimer disease.
Genetic Tests For Dementia On The Nhs
The NHS offers genetic testing for people believed to be at risk of an inherited form of dementia, for example frontotemporal dementia or some forms of younger-onset Alzheimer’s disease. This includes people who have a close relative who has been shown to have an inherited form of the condition or people with several relatives developing dementia when they are younger than 65 years of age. In these cases, genetic counselling is available if required, both before the test is taken and after the results. The self-testing kits do not offer any form of pre-test genetic counselling and don’t directly offer customers counselling after they are tested.
Due to the complex risk factors that lie behind the more common form of Alzheimer’s disease, the NHS does not offer a genetic test for it. The NHS does not test for APOE type or use this as a basis for diagnosis.
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Alzheimer’s Society’s View On Genetic Testing 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.
How Is Alzheimers Disease Diagnosed
If you are concerned about symptoms, its important to talk to your doctor or healthcare professional. As part of its Healthy Brain Initiative, the CDC emphasizes the importance of early detection, which gives people and their healthcare providers information, care, and support for their diagnosis.
According to the CDC, people are typically not aware that they have the condition through much later. Its only when symptoms become increasingly disruptive, for instance when someone gets lost in a familiar place, that leads to the condition first getting diagnosed.
A doctor evaluating someone with early signs of Alzheimers disease may do cognitive tests and then refer them to a specialist for further testing. Some of those additional tests may include brain imaging and/or lab tests to look for signs of the disease, which can include structural changes in the brain or changes in levels of certain types of proteins.
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