What does it mean for you if your parents have Alzheimer’s disease? For actor Chris Hemsworth, best known for his portrayal as Thor in Marvel movies, knowing he has a heightened risk of developing the disease meant taking “preventative steps” and taking off of filming to spend more quality time with his children and wife [1].
At age 39, Hemsworth learned that he has two copies of the gene APOE4, one from each of his parents, making him 8-10 times more likely to develop the disease. He also belongs to the 2 to 3% of the population carrying two copies of the gene [1] [2].
Although APOE4 is considered a risk-factor because it increases the risk of developing Alzheimer’s disease, inheriting it does not mean that a person will definitely develop the disease [2]. Some people with the gene never get the disease, and conversely, others who have Alzheimer’s do not have any of APOE genes [2]. Furthermore, the NIH notes that rare forms of APOE may provide protection against Alzheimer’s, but more studies are needed to support the variations that lead to delaying onset or lowering a person’s risk [2].
So while genetic testing will inform you on which risk factor genes you have, identification of APOE or other variants in your genes cannot determine your specific likelihood of developing Alzheimer’s disease [2]. The NIH further says that genetic testing is unlikely to predict the disease accurately because there are many other factors that drive its development and progression [2].
Fortunately, many of these factors are controllable. Science has shown a correlation between a number of brain-health factors and the onset and progression of cognitive decline [2, 3]. These include getting proper deep and REM sleep, managing blood pressure, eating a brain-healthy diet, getting proper mental stimulation, and exercising regularly. It’s of course smart to work on these factors regardless of your genes, but people with higher genetic risk should be even more focused on the things they can control, ultimately reducing their overall risk.
References:
- BBC News, November 21, 2022. “Chris Hemsworth: Alzheimer’s risk prompts actor to take acting break,” BBC News Entertainment and Arts. Accessed December 12, 2022 https://www.bbc.com/news/entertainment-arts-63668310
- National Institute on Aging, December 24, 2019. “Alzheimer’s Disease Genetics Fact Sheet,” NIH NIA. Accessed December 12, 2022 https://www.nia.nih.gov/health/alzheimers-disease-genetics-fact-sheet
- Alzheimer’s Disease Research Center, February 18, 2020. University of Wisconsin-Madison School of Medicine and Public Health. Accessed December 12, 2022 https://www.adrc.wisc.edu/dementia-matters/dna-not-your-destiny-genetics-and-alzheimers-disease-risk