FDA Approves Direct to Consumer Genetic Test for Alzheimer’s
Curious to learn if you have a genetic mutation for one of ten inheritable diseases, including Alzheimer’s? The Food and Drug Administration just gave the stamp of approval for the first time to a direct to consumer genetic testing company, 23andMe, to offer a genetic test for Alzheimer’s and more. Selling genetic testing kits directly to consumers, without going through a health care provider, is nothing new. 23andMe is the first company, however, to win the FDA’s approval. 23andMe makes testing for genetic diseases as easy as spitting in a cup. But is it a good idea to know if you have a genetic mutation for Alzheimer’s? The answer is not so simple.
Genetic Testing for Alzheimer’s with 23andMe
Back in 2013 the FDA turned 23andMe down. They cited the need for proof that results are accurate. They also wanted better follow-up and counseling regarding results. After all, clients notified that they have a genetic mutation for Alzheimer’s, Parkinson’s, celiac disease, or one of the other genetic diseases, may need professional guidance. Now 23andMe, which is based in Mendocino, California, provides a link to genetic counselors to set up an appointment to discuss results. The $199 charge for 23andMe’s Ancestry and Health home kit does not include fees for genetic counseling.
Collecting samples at home really is as easy as spitting in a cup. The mucosal cells that line the mouth slough off into saliva, providing DNA without the need for drawing blood. Clients must specify if they want to include testing for Alzheimer’s and Parkinson’s.
What to Know Before You Test for Alzheimer’s
What about you? Are you thinking about buying a genetic test for Alzheimer’s disease? It’s important to understand a few facts. First, Alzheimer’s disease is linked to over 25 identifiable gene variants. 23andMe tests only for the ApoE4 gene — the one associated with the late-onset Alzheimer’s disease that afflicts people after the age of 60. Early-onset Alzheimer’s disease, a devastating form that afflicts multiple family members in their 30s, 40s, and 50s, is linked to a different genetic mutation.
Second, testing positive for the ApoE4 gene does not mean you will definitely be diagnosed with Alzheimer’s. It doesn’t mean you won’t get it either if you test negative. ApoE4 is jut one of many genes linked to Alzheimer’s. Also, we don’t know if all cases of Alzheimer’s are linked to a gene. To make matters even more complicated, there are other types of dementia that are not the same as Alzheimer’s disease. In fact, blood vessel disease, such as atherosclerotic plaque, is the likely cause of up to 20% of dementia.
Testing for the ApoE4 gene can help calculate your risk of a future diagnosis, however, depending on how many copies you inherited. Those that are heterozygous (carrying one copy) for ApoE4 have a threefold increased risk of Alzheimer’s. Those who are homozygous for ApoE4 (carrying two copies) have a 15-fold increased risk.
How Will an ApoE4 Test Impact Your Life?
Third, and this is a big one, it’s important to think about what you will do with the result before you get the test. Will it make you anxious or depressed to know there’s an Alzheimer’s diagnosis lurking in the future? Will it help you change any habits that could reduce your risk of Alzheimer’s? What about how to communicate the results? Will you tell your friends and family? Will you divulge the results to your adult children?
Since the FDA’s approval of direct to consumer genetic testing, physicians are anticipating an avalanche of patients with genetic results. They are going to need help figuring out what to do with the information. What do the Alzheimer’s experts say? Dr. Martha Stearn, cognitive health specialist and creator of the Brain Works dementia prevention program at St. John’s Hospital in Jackson, Wyoming, says “I don’t recommend ApoE4 testing and neither do many leaders in the field.”
“The best thing is to live as healthy a lifestyle as possible and the genetic information should not affect that choice.”
Martha Stearn, M.D., cognitive health specialist
The Bottom Line: Genetic testing for Alzheimer’s disease is available but not always a good idea. Do your homework first. Find a health care provider who can help you weigh the pros and cons of testing. Since ApoE4 testing cannot determine with certainty who will or will not get Alzheimer’s, why don’t we all just live a brain healthy lifestyle?
Learn More: For a deep dive into the science of the genetics of Alzheimer’s disease, read this National Institute of Health 2014-2015 Alzheimer’s Disease Progress Report.