Genes That May Influence Alzheimers
The above-linked Alzheimers Society article is informed by responses from Professor Nick Fox, Honorary Consultant Neurologist at the Institute of Neurology in London. The article tells us:
- 99% of Alzheimers cases are not hereditary. And since the most significant risk factor is age, its not uncommon to have a parent or grandparent with Alzheimers disease who is in their late 70s and 80s. In that same 99% of Alzheimers cases, your risk of inheriting of Alzheimers compared to the rest of the population is very slight.
- In less than 1% of all Alzheimers cases, there is a very rare type that is hereditary. Early-onset Familial Alzheimers Disease, , described here and here, affects between 2-3% of the population. If a physician diagnoses you with eFAD, one of your parents will have had the disease if they lived long enough. In addition, your siblings and children may have a 50-50 chance of inheriting eFAD. Note that early-onset Alzheimers usually occurs in individuals who are in their 30s, 40s or 50s. In rare cases, it occurs when a person is in their 20s.
- Researchers have discovered that certain genes will cause early-onset Familial Alzheimers Disease if they have a specific kind of mutation or change. Known as PS1, PS2 and APP, the full names of these genes are: Amyloid precursor protein gene APP on chromosome 21 Presenilin 1 on chromosome 14 and presenilin 2 on chromosome 1.
How Can I Reduce My Risk Of Dementia
For the vast majority of people, our genes are only one factor affecting our risk of dementia. There are many other factors involved, such as age and lifestyle. While we cannot change our age or genes, research has found that up to a third of all cases of dementia could be avoided through lifestyle changes.
There are simple things we can do that may help lower our risk:
- Do not smoke.
- Drink fewer than 14 units of alcohol per week.
- Control high blood pressure.
- Keep cholesterol at a healthy level.
- Keep active and exercise regularly.
- Maintain a healthy weight.
- Eat a healthy balanced diet.
You can find more detailed information about how you can reduce your risk of dementia here.
Scientists Cant Say For Sure Whether Family History Predicts Alzheimers Or Not
There is one rare type of Alzheimers disease, called early-onset familial Alzheimers disease , that is known to be genetic and will appear throughout a family tree. However, this accounts for only 5 percent of all Alzheimers cases.
For the rest, Alzheimers research is not conclusive. Some studies indicate that people with a parent or sibling who has Alzheimers have a slightly higher risk of developing it themselves. But experts hesitate to say for sure whether youre considerably more likely to develop Alzheimers if a family member has it.
Patrick Lyden, MD, neurology professor at Cedars-Sinai in Los Angeles, told The Mighty this idea has gotten into the public mindset likely due to news reports about the rare family-inherited dementias, but there isnt a definite one-to-one risk for Alzheimers. In fact, this is one of the most common misconceptions he encounters.
If you have one parent with Alzheimers and youre worried about your own risk, thats where we really dont know, Lyden said. In some cases those are hereditary, but a lot of times when youre talking about something thats so common, it might just be a coincidence.
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Can Genetic Alzheimers Disease Be Predicted
People who suspect their family may carry one of these genes can now choose to have testing done to find out. This allows you to know if you are going to develop the disease so you can be prepared.
Early-onset Alzheimer’s disease can have devastating effects on the careers, caretakers and family members of people who develop the disease.
Many individuals who develop genetic Alzheimers disease early on in life are still raising children. Children who are not entirely grown are affected physically and emotionally as their parents lose the ability to care for them.
Knowing their likelihood of developing the disease gives people the opportunity to make choices and put plans in place regarding their childrens care while they are still able to do so.
Those who are working may lose their ability to perform their jobs competently and may find it necessary to take early retirement. When this can be predicted, employees have the opportunity to discuss their future with their employers and the loss of skills that they expect to face.
Other people may choose to retire if they are financially able so that they can enjoy their time while they are still fully able.
While there are certain benefits to be had from predictive testing, it is also possible the knowledge you are likely to develop such a disease could have serious implications for your mental health.
Causes Of Alzheimers: Is It Hereditary
Increasing cases of Alzheimers disease
The Alzheimers Association states that Alzheimers disease is the sixth leading cause of death in the United States, and that more than 5 million Americans are affected by the condition. Additionally, one out of three seniors dies of Alzheimers or some other type of dementia. That number will likely increase as the aging population increases.
Scientists have been researching Alzheimers for decades, but still there is no cure. Learn more about how genes are related to the development of Alzheimers, as well as other potential causes of the condition.
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Is Bipolar Disorder Hereditary
We have known for some time that bipolar disorder can run in families, and now, with genomic sequencing, we are learning about the possible role of genetic factors in the disorder. While the role of heredity is clear from family and twin studies, further research is needed.
Let’s look at what we know about family history and bipolar disorder, and then at what genetic specialists have discovered about the role of individual genes in both bipolar disorder and other mental health disorders.
Finding Out Your Genetic Or Hereditary Risk May Not Ultimately Affect You
Because risk factors like blood pressure and diet are more influential than genetics , you might ultimately decide that you dont really need to know your genetic or hereditary risk. Anyone, whether they have a family member with Alzheimers disease or not, can benefit from working to lower their risk.
A lot of my patients decide against . Because what are you going to do? Youre going to do diet and exercise, Lyden said. So if youre going to do diet and exercise anyway, why bother finding out that you have this gene.
If you just found out a relative has been diagnosed with Alzheimers disease, try not to jump to the conclusion that you will 100% get it, too. Science does not indicate you need to assume your diagnosis is coming. For the best chance of lowering your risk of Alzheimers, focus on maintaining a healthy lifestyle. And if you have a loved one with Alzheimers and are looking for support, check out these articles written by people who have been there:
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Cause #: Past Head Trauma
The Alzheimers Association states that scientists have found a link between traumatic brain injury and a greater risk of dementia. After a traumatic injury, your brain creates large amounts of beta amyloid. This is the same protein that develops into the damaging plaques that are a hallmark of Alzheimers.
Theres one difference: After a traumatic brain injury, beta amyloid, although present, doesnt clump into plaques. However, the damage may increase the risk of them doing so later in life.
Vascular Issues May Also Play A Role In Alzheimers Disease
Vascular problems those related to blood vessels, such as beta-amyloid deposits in brain arteries, ministrokes, and hardening of the arteries may be a cause of Alzheimers disease as well as a result of it.
Damaged arteries harm the brain by reducing the flow of blood, depriving brain cells of oxygen and essential nutrients like glucose preventing the elimination of toxic beta-amyloid and tau proteins and leading to damaging inflammation.
Researchers are working to identify exactly how and why this happens with the goal of interfering with this cycle.
A study published in 2017 in the Journal of the American Medical Association , following 322 subjects for over 20 years, found a relationship between vascular risk factors in middle age obesity, smoking, high blood pressure, diabetes, and high cholesterol and amyloid plaques in the brain.
The researchers found that subjects who had one risk factor had an 88 percent increased risk for elevated levels of amyloid plaques. People with two or more risk factors had almost triple the risk.
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How Can Dementia Be Prevented
Image via Pixabay
Genetic predisposition to dementia does not make it unavoidable. Certainlifestyle modifications were proven toreduce the risk of this condition or slow down its development. Having a job that involves mental tasks reduces the risk of dementia later in life. So does the healthy lifestyle and diet.
Even in the case of highly heritable Huntingtons disease, it was demonstrated that regular physical exercise helps to postpone the onset of the disease.
On the other hand, high blood pressure increases the risk of vascular dementia. Chronic stress and depression were also associated with higher chances of getting Alzheimers disease at an older age.
Recent discoveries about the causes and risk factors of dementia point to strong genetic components in the development of this condition. However, genes only predispose a person to the development of dementia. In the majority of cases, the contribution of various environmental and lifestyle factors is needed to trigger the disease development. Knowing the risk factors can help in reducing the chances of dementia at an older age. It can also help in managing the patients more effectively and slow down the disease progression.
Like with any other chronic condition, early detection is important for better treatment and management of dementia. TheBrainTest® app can help in detecting the early signs of cognitive decline. Timely identification of problems allows slowing down the development of the disease.
Is Frontotemporal Dementia Hereditary
Frontotemporal dementia is a number of different ailments caused by the progressive loss of nerve cells specifically from the brains frontal or temporal areas. It includes changes in temperament, behavior, and language skills.
Frontotemporal Dementia is rare, but it can be passed on directly from parent to child.
About 33% of everyone affected by it has a family history of this type of dementia. It is inherited because of a single mutation on a specific gene. Those worried about inheriting FTD or passing it on to their children can get a referral from their general practitioner to a genetic testing service.
FTD usually has an earlier onset than Alzheimers and vascular dementia as early as age 40. The first noticeable characteristic is often language difficulty.
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A Mysterious Disease Has Plagued This Family For Generations They May Be On The Verge Of Answers
The Lowman sisters didnt know the Bagwells they were three generations removed. They didnt know about Pierre Chastains many descendants. But when they heard from Levey that their kinship might hold the key to a cure, they got to work.
They called their cousins and people they hadnt even known were kin. They invited Emory researchers to the poolside reunion of Mildred Lowmans branch of the family. Virginia Rutledge, a younger cousin who owns a testing lab, offered Chastain Days. Family members lined up to give blood at the clinic, where a paper scroll displaying the family tree stretches around the lobby and down a hallway. Rutledge and another cousin who is a phlebotomist attended national Chastain family reunions to take blood.
The more branches get involved in it, the better the chance of finding that common gene, Dunn said.
Neurogeneticist Dr. Thomas Wingo, who began his work as a fellow with the Emory Alzheimers Disease Research Center in 2008, recently selected seven Chastain family members with Alzheimers from different branches and began sequencing their genomes. He was looking for genetic changes, or variants, that they share but are rare or not found in the general population. Emory has blood samples from unaffected, unrelated people to use as controls.
He has tested about 2,000 variants. Four are significant which means they may be associated with Alzheimers disease. More testing will confirm or refute the finding.
Dr. Thomas Wingo, neurogeneticist
Can Vascular Dementia Be Inherited
In most cases, vascular dementia itself is not inherited. However, the underlying health issues that sometimes contribute to this condition, such as high blood pressure or diabetes, may be passed on from one generation to another.
Other than in a few, very rare cases, parents cannot pass on vascular dementia to their children. However, a parent may pass certain genes that increase the risk of developing vascular dementia.
The sort of genes that increase the risk of vascular dementia are often the same ones that increase the risk of high blood pressure, diabetes, heart disease and stroke.
For this reason, having a healthy lifestyle, such as eating well and staying physically active, are probably more important for preventing vascular dementia than they are in Alzheimer’s disease.
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Is Dementia Passed On Through Our Dna
Medical research seems to suggest that it is very unlikely that dementia can be passed on through our DNA. But in rare cases, some diseases that lead to dementia can be passed on through our DNA. But it is still extremly rare that if a family member such as a parent or grandparent has developed one of the many different kinds of dementia, that their children will inherit the disease at some stage in their life.
This is not to say that somebody with Alzheimers cannot have not passed on the disease from parent to child. It is possible they could have. In some rare cases of Alzheimers, the disease can be inherited from a parent. But this is very rare.There is a group of four genes a person can carry that can lead to a greater risk of Alzheimers. With 3 of the four genes being responsible for early onset dementia in people in their 30s, 40s and 50s with the other gene being responsible for Alzheimers in older people, usually over 65 years of age.
In the majority of cases of Alzheimers the disease is mostly associated with old age. Most cases are diagnosed with people in their 70s and 80s which is often referred to as Senile dementia.
What Are The Symptoms Of Early
The symptoms of early-onset Alzheimers disease are much the same as when the disease develops in later life.
Early signs of Alzheimers disease include unexpected memory loss, especially when recalling recent events and the names of familiar people and things.
As the illness progresses, patients develop more severe problems, such as becoming subject to mood swings and being unable to perform complex tasks, like driving.
In the latter stages of Alzheimer’s, they may forget how to do simple things like brushing their hair. It is likely that they will require full-time care towards the end of the illness.
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Is Normal Pressure Hydrocephalus Hereditary
A buildup of cerebrospinal fluid in certain parts of the brain can cause a condition called normal pressure hydrocephalus that causes dementia, difficulty walking, and bladder-control problems. Normal pressure hydrocephalus can be hard to detect because most people who develop it are between age 60 and 80, and NPH shares symptoms with other types of dementia.
A 2011 study of two sisters with NPH reported in the Canadian Journal of Neurological Sciences found that each woman had the same set of protein alleles on her 19th chromosome, which indicates there may be a genetic role in at least some cases of NPH. Most of the time, theres no known cause, although infections and bleeding into the brain cause some cases of NPH.
The only effective treatment for NPH is surgery to place a shunt in the brain to drain the extra fluid in some cases, patients ability to walk improves post-surgery. The Alzheimers Association says that cognitive and bladder problems are less likely to improve.
Alzheimers And Down Syndrome
Down syndrome may give researchers hints at how the 21st chromosome affects the development of Alzheimers disease.
In Down syndrome, an individual has an extra copy of chromosome 21. This 43rd chromosome overall leads to symptoms, such as a flattened facial appearance, slant eyes, short neck, small ears, small hands and feet, and intellectual and/or developmental problems.
Moreover, individuals with Down syndrome develop Alzheimers at a much higher rate than the rest of the population, and at a much younger age.
Since Down syndrome seems to increase risk of Alzheimers disease, scientists believe the APP gene, which is present on chromosome 21, playsa major role in Alzheimers development.
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Is Alzheimers Disease Hereditary
Family history is a strong Alzheimers disease risk factor, meaning that if you have a first-degree relative such as a parent or sibling with the disease you are more likely to develop it yourself.
But that doesnt mean that Alzheimers disease is hereditary. Researchers believe that genes do not directly cause Alzheimers except in an estimated 1 percent of all cases involving gene mutations passed directly from parent to child.
If youve inherited one of three gene mutations from either your mother or father, you have a very high probability of developing a highly uncommon form of Alzheimers called familial early-onset.
This is not a common condition: Scientists have been able to identify these mutations in only 500 families around the world.
For the vast majority of people, certain genes increase the risk of Alzheimers disease but do not guarantee it.
Many people with these genes will never develop Alzheimers, because lifestyle and environment also play a role.
Scientists are studying the complex interactions between all these factors to understand Alzheimers disease causes and to learn whether its possible to keep them at bay.