The market for at-home genetics testing has exploded. Companies like Family Tree DNA, 23andMe and Ancestry.com claim you can learn everything from your heritage to your propensity for developing diabetes by spending a few hundred bucks and spitting in a vial.
It’s a tantalizing proposition, to be sure, but for many consumers, one question remains: Are these tests really accurate?
To answer that question and more, we asked Henry Ford genetic counselor Lexie Gohlke, M.S., to weigh in.
Q: Can you explain what at-home genetic testing is?
A: Direct-to-consumer genetic testing and at-home genetic testing describe the same technology. You order a kit online and the company sends it to your house or you can buy a kit at some major retailers. You spit in a vial, so the company can collect a sample of your DNA (the complex molecule that contains your unique genetic code) and then send it back. Once the lab receives the saliva sample, they analyze something called single nucleotide polymorphisms, or SNPS. These SNPS are different among geographic populations. After a few weeks, you hop online and retrieve a report identifying some of the geographic locations where your ancestors have come from. Some companies only include information about ancestry. Others may offer insight about everything from whether you carry genes that raise your risk of developing certain cancers to whether you blush when you drink alcohol.
Q: How reliable are the ancestry results?
A: Every lab uses different reference DNA, so you may get different ancestry information depending which company you choose. Every lab might have slightly different, but still correct, information.
Q: What are some of the caveats with at-home genetic tests?
A: Companies like 23andMe use SNPS to determine your likelihood of developing certain diseases. Unfortunately, there are a lot of misconceptions about how to interpret the results. For example, 23andMe recently began providing customers with information about two genes, BRCA1 and BRCA2. Both of these genes protect our body from cancer, so a mutation in one of them could increase your risk of developing cancer. Unfortunately, more than 1,000 other gene mutations can also increase your risk of cancer. So, a negative result doesn’t offer much insight about your real risk of developing cancer.
You might also learn information about your heritage, or your assumed biological family members, that you didn’t know. Sometimes people uncover parental infidelity or previously unknown family members. And sometimes they don’t match up with people they assumed were biological relatives. It’s important to consider all possibilities before you undergo testing.
Q: How do at-home tests differ from physician-prescribed genetic tests?
A: Physician-prescribed tests require a detailed consent process. Instead of reading a blanket disclaimer on a computer monitor, patients sit down with a genetics professional before testing. They learn the benefits (and drawbacks) of testing and what the results might mean. Physicians use specialized laboratories to analyze DNA, and when the results are in, doctors and genetics counselors interpret them.
The Big Picture
Genetic research is increasing and the number of diseases we can detect through genetics is on the rise. “But genes are just one piece of a complex puzzle – and it’s important to consider the fallout of test results before you get tested,” Gohlke says.
Not only can ancestry testing reveal unexpected findings, but genetic testing for specific disease states can cause undue stress. If your results indicate an elevated risk of a condition with no intervention, like Alzheimer’s disease, you could be stuck with a feeling of impending doom even though you might never develop the disease.
The bottom line: If you have concerns about heritable conditions, talk to a genetics counselor. Similarly, if you’ve tested positive for any genetic mutations on an at-home genetics test, confirm it with a genetic testing lab.
You can learn about your genetic risks by making an appointment with a genetic counselor at Henry Ford. Visit henryford.com or call 1-800-HENRYFORD (436-7936).
Lexie Gohlke, M.S., is a genetic counselor and sees patients at Henry Ford Medical Center – New Center One in midtown Detroit.
