- Chris Hemsworth has discovered that he may be at a higher risk of developing Alzheimer’s disease.
- A genetic test revealed that Hemsworth has two copies of the APOE4 gene
- The APOE4 gene has been associated with an increased risk of Alzheimer’s disease.
Actor Chris Hemsworth announced that the results of a genetic test he took revealed that he is at a higher risk of developing Alzheimer’s disease because he has two copies of the APOE4 gene.
The APOE gene (apolipoprotein E) is partial responsible for how brain cells deal with fats and stress, and it has 4 known variants.
Humans get one of 4 variants of this gene from each parent. Versions 1-3 of the APOE gene each carry their own risk of impaired brain health, but version 4 is associated with the highest risk of all versions.
For those who received 2 copies of the APOE4 gene (one from each parent), such as Hemsworth, their risk of developing Alzheimer’s disease is 8 to 10 times greater than the average person.
However, people who have 2 copies of the APOE4 gene are very rare.
Nevertheless, Hemsworth’s announcement has increased curiosity about genetic testing, with people wondering if they should do the same to make more informed choices about their health.
The first thing to know about the ongoing public conversation around the gene is that it is related to risk sensitivity and not what is known as deterministic.
This means that having two copies puts you at a higher risk — as much as ten times that — but that doesn’t mean you’re automatically going to get the condition.
This is different from conditions such as Huntington’s disease, where the chance of getting the condition is almost certain if you have the correct mutation of the gene.
“It’s a big difference between a genetic test showing a mutation, meaning you’ll get it anyway. There is no lifestyle [element]. There’s nothing that activates the genes like Huntington’s disease or sickle cell anemia. Compared to something like Alzheimer’s, that’s what the [researchers] regard as multifactorial, Karen Sullivan, PhDa board-certified neuropsychologist told Healthline.
One benefit of genetic testing is that — given the right circumstances — it can motivate lifestyle changes that can reduce your risk.
Dustin Hines, PhDco-director of the Hines Group Comprehensive Neuroscience Lab at the University of Nevada – Las Vegas, told Healthline that the debate over whether or not to undergo genetic testing is a common topic at his dinner table.
“This is one of the things we always debate: would you get one of these 23andMe screens to see what you have and what you don’t? I would get tested like this, I think knowledge is power. However, that is my personal opinion, but it is very personal what you want to do with it.”
Hines says it’s helpful to contextualize genes as partially fluid rather than static entities.
“Not all genes are expressed equally during an individual’s lifetime. So certain things, like the environment, like stress, can either increase or decrease genes. And in fact, we’ve recently learned that the clinical idea that you’re born with these genes and they’re set in stone isn’t actually even true. There is an entire field of epigenetics that now shows that your genes can change even within a lifetime.”
Widely accessible genetic testing, such as that offered by services like 23andMe, has thrust genetic testing into the spotlight, making headlines and capturing the attention of the mainstream.
However, Sullivan says patients really need to make sure they’re prepared for the answers they may get, especially when Alzheimer’s is one of the most feared conditions among the elderly.
Nevertheless, Sullivan emphasizes that genetic testing can be valuable if your support system is there and if you can turn the results into momentum for yourself and others.
“What this genetic test allows us to do is that when someone is 21 years old, they might look down on the next few decades of their life and [ask], perhaps they are experiencing humanity’s most dreaded disease. So there is a huge emergency current. And I want people to get empathy out of that. I want them to understand what it might be like to be in those shoes. So, now that you know what you know, how are you going to join our cause to improve dementia care?”