Last week, the personal genetics company 23andMe announced that it received FDA approval to offer genetic information for 10 health risks (after demonstrating that its reports are accurate and easy to understand). The 10 new genetic risk reports include one for late-onset Alzheimer's, the most common form of the disease.
In its late-onset Alzheimer's report, 23andMe provides people with their APOE gene variant. APOE is associated with varying risk of developing Alzheimer's, and there are three possible types. APOE3, found in about 70% of the population, is the most common variant and is considered neutral. APOE2 is the rarest form, found in 5-10% of people, and is associated with reduced risk of Alzheimer's. APOE4, found in 10–15% of the population, is associated with a greater risk. Everyone has two copies of the APOE gene: people with E2/E2 have the lowest overall risk for Alzheimer's and those with E4/E4 have the highest risk. The other combinations of APOE—E2/E3, E2/E4, E3/E3 and E3/E4—fall in between.
It is important to note that having the APOE4 gene variant does not mean you will definitely develop Alzheimer's disease. We know from prevention research that people with the APOE4 gene can take a number of steps to mitigate their risk. Observational studies suggest that managing mid-life hypertension may be more beneficial for APOE4 carriers than non-carriers . Also, the association between type 2 diabetes and Alzheimer's disease risk is greater in APOE4 carriers than non-carriers, which makes it even more important for those with APOE4 to prevent or effectively manage diabetes . In fact, all of Cognitive Vitality's First Steps can help lessen the risk of Alzheimer's disease later in life, regardless of APOE status.
The 23andMe genetic tests require a saliva sample, which is mailed back to the company. It's important to note that the National Institutes of Health only recommends genetic testing of APOE status for people volunteering for clinical trials. Understanding the risk for certain diseases based on genetics is complicated, and people considering such tests may want to consider genetic counseling. To find out more about what APOE means to your health, visit Cognitive Vitality's APOE page. Additional information, including personal accounts from people with the APOE4 variant, can be found at ApoE4.info.
Nick McKeehan is Assistant Director, Aging and Alzheimer's Prevention at the Alzheimer’s Drug Discovery Foundation. He served as Chief Intern at Mid Atlantic Bio Angels (MABA) and was a research technician at Albert Einstein College of Medicine investigating repair capabilities of the brain. He received a bachelor of science degree in biology from Purdue University, where he was awarded a Howard Hughes Scholarship. Mr. McKeehan also writes about the biotechnology industry for 1st Pitch Life Science.
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