What Are the Odds That a Person Will Inherit the Dominant Gene for Alzheimer’s Disease?

Alzheimer‘s disease is a progressive brain disease associated with a loss of memory, judgment, and functioning abilities. Most forms of this disorder appear after the age of 65, but rarer forms can be seen during the adult years. The most common symptom of Alzheimer’s disease is memory loss. There are many causes of dementia, but Alzheimer’s is the most common. An Alzheimer’s patient may become lost or confused even in familiar surroundings. Routine chores like cooking, cleaning, and doing laundry can be tedious chores.

Moreover, recognizing people and naming objects may become more complex. Some people with Alzheimer’s disease experience personality changes and difficulty interacting socially as the disease advances. Scientists believe Alzheimer’s disease has no single cause. There are likely many factors that contribute to it, including genetics, lifestyle, and environment. Scientists have identified factors associated with Alzheimer’s. We can’t change some risk factors, like age, family history, and heredity. However, emerging evidence suggests that we can change others.

How Is Alzheimer’s Inherited?

Some genes may increase a person’s chances of developing the disease. One does not necessarily develop Alzheimer’s by having an Alzheimer’s parent. Genes play a role in disease development in two different manners: risk genes and deterministic genes. In both categories, genetic markers for Alzheimer’s have been found. The specific gene responsible for late-onset Alzheimer’s disease has not been identified.

Alzheimer’s Risk Genes

Alzheimer's disease and genes

Having risk genes increases the likelihood of contracting a disease, but this does not guarantee that it will be contracted. The risk of Alzheimer’s disease is increased by several genes found in researches. First identified as a risk gene, APOE-e4 continues to remain the most influential.

The APOE-e4 gene is present in between 40 and 65% of people with Alzheimer’s. The APOE-e4 gene is one of three common forms of the gene. From each parent, we inherit a copy of APOE. The other two are APOE-e2 and APOE-e3.

Alzheimer’s is more likely to develop in individuals who inherit one copy of APOE-e4. There is an even higher probability for those whose parents have two copies, but not a guarantee. APOE-e4 may also accelerate the onset of symptoms by raising the risk. Having an APOE-e4 allele, however, does not guarantee that one will develop Alzheimer’s disease. Some people with APOE-e4 alleles may never develop Alzheimer’s, and other people with Alzheimer’s do not have any APOE-e4 alleles.

Alzheimer’s Deterministic Genes

Families with these genes are more likely to suffer from familial early-onset Alzheimer’s in their 40s and 50s as symptoms develop between those ages. These rare genes directly cause Alzheimer’s disease, causing anyone who inherits them to develop it. A few hundred extended families worldwide have been found to carry a rare gene that causes Alzheimer’s. While hereditary genes associated with familial Alzheimer’s are rare, their discovery has provided important clues toward understanding the disease.

Is Alzheimer’s Inherited from Mother or Father?

An individual human cell contains the instructions it needs to function. DNA is composed of instructions, which are packed tight into structures called chromosomes. There are thousands of segments called genes on every chromosome. Biological parents pass down their genes to their children. Among other things, they describe specific characteristics such as body type, skin, hair and height. The body’s cells also depend on genes for their health.

Several genes have been linked to Alzheimer’s disease. But is dementia inherited from mother or father? Each parent passes on some form of APOE to us. Alzheimer’s is more likely to develop in individuals who inherit one copy of APOE-e4. It is a higher risk, but not a guarantee, for those who inherit two copies from their mother and father. A person can develop a disease despite carrying risk genes, but this does not guarantee it will occur.

Genetic Test for Alzheimer’s Disease

Alzheimer's disease and genes

Alzheimer’s is among The Common Mental Disorders that Threaten the Elderly. Blood testing can identify whether or not a person has an APOE-e4 allele, but it is not a predictor of Alzheimer’s disease. APOE testing is primarily used in research settings to identify participants who could be at a higher risk for Alzheimer’s disease.

Genetic testing is also available for the rare genes directly linked to Alzheimer’s. A genetic test for APOE-e4 cannot determine a person’s likelihood of developing Alzheimer’s disease; it only tells us which genes they possess are associated with the disease. According to researchers, there may be too many factors affecting the disease’s development and progression for genetic testing ever to predict it with 100 percent accuracy.

Scientists do not recommend general population genetic testing. Whether you are worried about the symptoms of Alzheimer’s disease or changes in your memory, then it’s best to talk directly to your healthcare provider.

Final Words

It is not necessary to have a family history for someone to develop Alzheimer’s. However, those with a parent, sibling, or close relative diagnosed with Alzheimer’s disease are more likely to develop it. The risk of Alzheimer’s disease increases even more for those with more than one first-degree relative who has the disease. Scientists believe Alzheimer’s disease has no single cause. The causes of Alzheimer’s disease and other dementias are either inherited or are environmental. There are likely many factors that contribute to it, including genetics, lifestyle, and environment. We can’t change some risk factors, but lifestyle changes can be helpful.

Use this article only as educational material. You must consult your doctor and/or specialist prior to using it. Read more about this disclaimer.

Source nia.nih alz
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1 month ago

My father and brother both had Alzheimer’s disease. Personally, while I should be frightened, I don’t care much for my own destiny. God was kind enough to make me a free spirit that is willing to accept anything that comes his way. But my mother was very worried about me until her last breath. My sister also got away with the disease, thank God. So I wonder if it’s possible for this disease to only develop in the males (or females) of a family.

29 days ago

Is there a blood test for Alzheimer’s? Not the one that shows if you have the APOE-e4 gene. My grandfather had Alzheimer’s; of course, we don’t know if he had Alzheimer’s or other forms of dementia. Because there was no way, they could diagnose it back then. One of my biggest nightmares is to inherit Alzheimer’s, or even worse, pass it on to my children. Will there ever be a cure for this disease? 

20 days ago

I want to believe that a healthy lifestyle can prevent Alzheimer’s, and I hope there’s a cure for this disease one day. It’s so scary, the brain starts dying, and you are not you anymore. I don’t know anyone who had it. I’ve only seen a couple of movies about Alzheimer’s; it is a horrible condition. 

17 days ago

I wish this disease did not bring terrifying notions with it. I am not trying to say it is not a big deal, but I am pretty sure the name and the idea of it are scarier than the disease itself, so when someone is diagnosed with it, it is hard for those who love them to prepare themselves mentally and be there for their loved one. Although, I still wish this disease did not exist, or at least I wish there was a definite cure for it.

6 days ago

I think apart from all the hardships that come with finding out your parent has Alzheimer’s, the fear of it being hereditary is also very exhausting. I wish well for everyone struggling with this disease and those who are struggling with the fear of it.