There are multiple factors which influence the chance that an individual will develop Alzheimer's. One of the largest factors is genetics, or family history.
Individuals with relatives, especially parents, with Alzheimer's are at a higher risk to develop the disease themselves.
The cause behind this link is a gene, called ApoE.
Genetics and Alzheimer's
ApoE, The Gene that Can Cause Alzheimer's.
Genes are parts of our body that determine numerous characteristics about us, from the color of our hair, to how tall we are. A gene called ApoE influences our likelihood to develop Alzheimer's disease.
ApoE affects the likelihood of developing Alzheimer's disease by influencing the amount of harmful plaques in the brain. ApoE is responsible for removing plaques from the brain, these plaques are believed to be one of the primary causes of Alzheimer’s.
The Risk of Developing Alzheimer's Depends on Which Version of the Gene You Have
There are three versions of the ApoE gene, the version you have is determined by which you inherited from your parents. Each version is different in how effective it is at removing the harmful plaques from the brain.
The three versions of the ApoE gene are:
ApoE 3 – Version 3 is the most common version, it removes plaques from the brain reasonably well. Individuals who have version 3 do not have an increased or decreased risk of developing Alzheimer’s.
ApoE 2 – Version 2 is more effective at removing plaques from the brain. Individuals who have version 2 have a reduced risk of developing Alzheimer’s.
ApoE 4 – Version 4 is less effective at removing plaques from the brain. Individuals who have version 4 have a significantly increased risk for developing Alzheimer’s.
Because ApoE 4 is not effective at removing these plaques from the brain, more of these harmful plaques build up and damage the brain. This explains why individuals with the ApoE 4 gene have a substantially increased risk of developing Alzheimer’s. If no preventative measures are taken, researchers believe that individuals with two versions of the ApoE 4 gene have a 50% chance of developing Alzheimer’s.
ApoE 4 Does Not Guarantee That Someone Will Develop Alzheimer's, Steps Can Be Taken To Reduce Alzheimer's Risk
Research has shown us that individuals with the ApoE 4 gene are able to reduce their risk for developing Alzheimer’s. Individuals with the ApoE 4 gene can reduce their risk by proactively managing other risk factors and by pursuing activities and lifestyles which have been shown to reduce the risk of Alzheimer’s.
Individuals with the ApoE 4 gene are more vulnerable to certain factors which increase the risk of Alzheimer’s, risk factors like diabetes or high blood pressure. This makes it even more important than normal for individuals with the ApoE 4 gene to manage their blood pressure and diabetic status.
The chance of developing Alzheimer’s is influenced by behaviors that occur decades before and leading up to when the symptoms first become noticeable. Individuals with the ApoE 4 gene should begin addressing risk factors sooner, rather than later.
Individuals with the ApoE 4 Gene Who Are Experiencing Memory Loss Should Speak with a Physician.
In addition to managing the risk factors discussed above, individuals who test positive for the ApoE 4 gene and believe that they are experiencing memory loss should consult their physician. Prescription medicines are available for Alzheimer’s. While these prescription medicines cannot cure Alzheimer’s, they can help with the symptoms and treatment is most often better started early than late.
Who Should Be Tested?
Individuals who have a family history of Alzheimer’s and individuals who believe they are experiencing memory loss should be tested for the ApoE 4 gene. Other individuals can be tested, but individuals in these two groups are most likely to possess the ApoE 4 gene.
Before being tested it is important to consider the emotional consequences of learning your result and how the result may affect you and your loved ones.
We believe that emotionally-stable individuals willing to take a proactive approach to managing their Alzheimer’s risk will benefit from genetic testing.
The Alzheimer's Organization in partnership with Kashi Labs offers at-home genetic testing for the ApoE 4 gene.
Learn More: The Alzheimer's Organization ApoE Genetic Test
A concise introduction to Alzheimer's, what causes it, and how to prevent and treat it.