If My Grandparents Have Alzheimer’s, Will I?

Is Alzheimer’s Hereditary from Parents or Grandparents?

By Heather Konrad RN, quality care coordinator at Network Health

As of 2023, Alzheimer’s is ranked the seventh leading cause of death in the United States, and it is estimated that over six million people in the U.S. have the disease. It’s also the most common cause of dementia.

Despite how common Alzheimer’s may be, some misconceptions remain about the role genetics play in the development of the disease. Many people see their parents or grandparents struggle with the disease and wonder if that means they will have a higher risk for developing Alzheimer’s themselves. We’ll provide answers to such questions in this article.

But first, let us provide a brief definition of what Alzheimer’s is for those who may be experiencing the disease for the first time. Alzheimer’s disease is the most common type of dementia. It is a progressive condition that affects various cognitive functions such as thought, memory, and language. While the disease primarily affects older individuals, there are instances where it can manifest at an earlier age.

Is Alzheimer’s Hereditary?

As mentioned, many people first experience Alzheimer’s when their parents or grandparents suffer from it, and they then wonder if they will develop it also. The good news is that the vast majority of Alzheimer’s cases are not inherited.

In fact, more than 99 percent of cases are not inherited, meaning that even if your parents or grandparents suffer from Alzheimer’s, you will not necessarily be at an increased risk. So, if inherited genetics is not the most important risk factor, what is?

You might have already guessed it. The most significant risk factor is age. Alzheimer’s is most common in people who are in their late 70’s or 80’s. When the onset of Alzheimer’s occurs at this age, it is likely to fall within that 99 percent of non-inherited cases.

Early Onset Alzheimer’s Disease

That said, Alzheimer’s can occur in younger ages too, even if it is less common. This is known as young onset Alzheimer’s disease. In instances where the disease develops at an age under 65, there is a greater chance that it is the inherited type of Alzheimer’s caused by a faulty gene and can be passed on to subsequent generations. Data shows 6.3 per 100,000 people per year will develop the disease between the ages of 45-64. The earlier the disease develops the more likely it is to be caused by genetics.

The APOE gene is what plays a role in Alzheimer's disease risk. There are at least three versions, or alleles, of the APOE gene. These are e2, e3, and e4. While the e2 allele (the least common) is associated with a reduced risk of Alzheimer's disease and the e3 allele (the most common) has no effect on Alzheimer’s risk, APOE e4 increases one’s chances of developing Alzheimer's disease when inherited. Having one copy of the e4 allele increases the risk, while inheriting two copies from both parents significantly raises the risk.

[Read more: Can Alzheimer’s Be Prevented?]

Is There a Genetic Test for Alzheimer’s Disease?

If you have a parent or grandparent who developed early onset Alzheimer’s disease, you may wonder whether genetic testing is available to see if you have a gene that might put you at risk. Genetic testing is possible, however, there are some things to consider.

For one, genetic testing is not routinely done for late onset Alzheimer’s. As mentioned, that variation of the disease is rarely inherited. As for early onset Alzheimer’s, there are some instances where genetic testing may be helpful. This includes testing prior to the start of certain therapies, such as anti-amyloid therapies.

That said, APOE genes are not usually tested for to determine a person’s risk factor. The results are not capable of fully predicting whether a person will or will not get Alzheimer’s disease. The presence of the APOE e4 gene does not guarantee it is the cause of the disease or even if it will develop. Moreover, genetic testing is generally not required for health care providers to determine if someone has Alzheimer’s.

Other Risk Factors for Alzheimer’s

As we said, age is a more significant risk factor than genetics and the same can be said for lifestyle factors. There is growing evidence that certain healthy behaviors can reduce the risk of cognitive decline and Alzheimer's disease. Such behaviors include the following.

• Regular exercise
• Blood pressure management
• A healthy diet
• Mental stimulation
• Stress management
• Physical activity
• Maintaining a balanced diet
• Challenging the brain with puzzles or learning new skills

While Alzheimer’s can be difficult and scary to talk about, know that your Network Health team is here to answer any questions you have about how our health plan can provide you the care, support and resources you need to manage this difficult disease. You can also find resources through the linked discussion below.