Is Alzheimer’s Hereditary?

In recent years, we have made some incredible advances within the field of neuroscience. Of particular interest are various degenerative conditions, as more and more individuals are affected. Since Alzheimer’s is the most common cause of dementia, this form has been significantly targeted regarding research efforts.

The more this disease is studied the more is understood, especially regarding genetics. If your mom or dad developed Alzheimer’s, it’s normal to worry and think, will you as well? Alzheimer’s is highly complex and there are various factors that can influence its onset. It’s important to note that although we have made incredible progress, there are still some unanswered questions.

Genetics and Alzheimer’s

Certain diseases are caused when a genetic mutation is experienced, resulting in permanent change. When individuals inherit these disease-causing mutations from either of their parents, they will likely develop the disease themselves. Classic examples of this are sickle cell anemia and early-onset Alzheimer’s.

In the case of genetic variants, this simply increases one’s risk of developing a specific disease, known as a genetic risk factor. When it comes to early-onset and late-onset, they both have a genetic component. When there’s a genetic mutation, for instance, this can lead to abnormal proteins, resulting in the development of early-onset Alzheimer’s.

Early-Onset and Late-Onset, How Do They Differ?

While focusing on genetics, it’s important to distinguish between early and late-onset. Although rare, early-onset develops between the ages of 30 and 60. The majority of cases are known as familial Alzheimer’s which is inherited. In other cases, the exact cause is not known at this time.

If your mother developed familial Alzheimer’s, for instance, you will have a 50/50 chance of inheriting that mutation and eventually developing the disease yourself. This mutation can occur on chromosomes 21, 14, and 1, causing abnormal proteins to form.

Most of the individuals who develop Alzheimer’s suffer from late-onset, developing symptoms in their mid-60s or later. At this time, the exact cause of late-onset is not fully understood, but it’s believed that a combination of genetics, lifestyle, and environmental factors play a role.

Researchers have not found a single gene that determines late-onset, however, apolipoprotein E (APOE) gene found on chromosome 19 appears to increase one’s genetic risk. This means that just because you inherit this gene, doesn’t mean that you will develop late-onset Alzheimer’s.

Some individuals who have this gene will never develop Alzheimer’s and other who do develop late-onset, do not have this gene at all. This is why researchers believe that your lifestyle and environment influence the development of Alzheimer’s, just as much as your genetic risk.

Can I Be Tested?

There are genetic tests that can be performed in certain cases. A blood test, for example, can detect APOE alleles, but these results will not be able to predict who will or will not develop this disease. If familial Alzheimer’s runs in your family, you can request testing. In many cases, however, individuals would rather not know.

NIH. (2015). Alzheimer’s Disease Genetics Fact Sheet. National institute on Aging. Retrieved from

https://www.nia.nih.gov/alzheimers/publication/alzheimers-disease-genetics-fact-sheet