While the tests can provide helpful information for diagnosing, treating, and preventing illness, there are limitations. Here are some things to consider before you jump in.

By Lisa Arbetter
June 04, 2020
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My dad told terrific stories, especially about his rough childhood in 1940s Brooklyn. He hinted that a few relatives were mobsters and swore that our family name was really something like Mandeira and that we are partially Spanish.

One thing my dad never talked about was the prominent scar on his neck. He let my siblings and me believe he was slashed in a fight on those dangerous Brooklyn streets. Shortly after I graduated from college, he revealed the truth. The scar resulted from an operation he had had to remove a cancerous tumor at the base of his tongue. Whatever they did kept the cancer in check for more than 20 years. It came back. He died about a year later.

His absence looms large in my life. I desperately wanted to maintain a connection to him…which is why I spit into a tube and sent it to 23andMe. I wanted to know if the Spanish association was real. And I figured while I’m spitting, I’ll pay the extra fee and find out if I might die of cancer, too.

The report said that my genetic heritage is 99.9 percent Ashkenazi Jew—which doesn’t rule out that my ancestors lived in Spain or were born there to a pair of Ashkenazim. As for the cancer, that’s not straightforward either. The test, which doesn’t actually screen for what my dad had, was negative for the cancers it does screen for—breast and ovarian. Whew, right? Not so fast. A negative is no guarantee you won’t get the disease. It just means they didn’t find the anomalies they were looking for. Even positive results can be difficult to interpret, since your ethnic group, family history, and lifestyle issues like smoking, drinking, diet, and stress are also important factors.

“Genetic testing is only one part of a complex process that includes genetic risk assessment, diagnosis, and disease management,” says Maximilian Muenke, MD, chief executive officer of the American College of Medical Genetics and Genomics. In other words, genetics is just one part of a very complicated puzzle.

What is genetic testing?

It’s a diagnostic medical test that can identify or confirm a specific genetic or chromosomal condition or the chance that you might develop it or pass it along. Doctors order up genetic tests for their patients, especially for those with a family history of a specific disease, and a lab processes them. The results can provide helpful information for diagnosing, treating, and preventing illness.

Since the Human Genome Project catapulted genetics to a whole new level in the early 2000s, gene analyses have become essential to medical research. At the same time, genetic testing crossed the bounds of science and medicine to private companies that developed and marketed direct-to-consumer (DTC) testing kits, which you could buy yourself without involving a doctor or another health-care professional.

How do the doctor-ordered and DTC kits compare?

The traditional route, if you have a family history or symptoms of a disease with a genetic component or are pregnant, is to have your doctor, a genetic counselor, or nurse practitioner send your sample to a clinical setting for testing. The labs, in this case, do what’s called gene sequencing, which looks at large swaths of DNA. These tests can be performed on blood, hair, skin, or amniotic fluid. Because results can be life-changing, doctor-ordered tests are accompanied both before and after by counseling from a health-care pro—a key component of the testing process. The results need no confirmation, and although these tests can be costly compared with DTC kits, they are usually covered by insurance.

I used a 23andMe genetic health test. DTC kits can screen for disease risk, help you choose a diet, or tell you how you might react to medication. Most DTC kits do an analysis called genotyping, derived from a saliva sample that you submit, which only looks for information at specific places in the DNA where we know essential data is located. Since the test isn’t as definitive as one from a doctor, nor does it take into account other data useful for risk assessment, such as ethnicity and lifestyle habits, DTC kit results should be confirmed by a medical professional.

Recently, hybrid options have become available. Ancestry, for example, rolled out two (starting at $179), which use the same sequencing technology as some of the tests your doctor may order. You fill out a family health history and collect your own sample, but the test itself is ordered through the company’s medical partner, PWNHealth. What you get back is an array of options for how much information you want and when you want it, with the choice to talk to a genetic counselor.

There are also some clinical labs—including Invitae; Color; and PerkinElmer Genomics, in collaboration with Helix—that allow customers to initiate tests online. You fill out a health questionnaire, and the request has to be approved by a medical professional. These labs provide a full sequencing analysis of all included genes, similar to other tests that your doctor might order, and counseling services. The cost ranges from $250 to $300.

How accurate are the results?

“If you are concerned about a disorder that runs in your family, the first step is to talk to a medical geneticist, who, based on your family’s history and a physical exam, can help identify which test is best for you,” says Dr. Muenke. Genotyping especially if you are at real risk, meaning you are showing symptoms or have a strong family history—isn’t what you want to rely on here.

Take the 23andMe report for BRCA1 and BRCA2: It includes three specific genetic variants in the BRCA1 and BRCA2 genes that are associated with an increased risk for developing breast cancer. To compare, clinical lab Invitae looks at all the variants in genes like BRCA1 and BRCA2 that can increase the risk of breast cancer. This approach gives consumers much more information, and helps them decide about making big life decisions, such as having a mastectomy. Still, considerations of time and expense (or simple curiosity) cause many people to start with DTC kits for their genetic data.

What should I do with the information I get back?

“When DTC genetic tests first came out, I was not a huge fan,” says Roshini Rajapaksa, MD, an associate professor of medicine at NYU School of Medicine, an attending physician at NYU Langone Health, and Health’s contributing medical editor. “I thought it was a Pandora’s box. But [the tests] have evolved. You don’t just get the results thrown at you.”

It’s good that patients are proactive about their health care, says Dr. Rajapaksa. “The more knowledge, the better,” she says. “But all of this info should be discussed with a doctor to avoid anxiety.” Also advised is a consultation with your health-care provider about confirmation testing (a follow-up clinical diagnostic).

Will the test affect my insurance coverage?

The Genetic Information Nondiscrimination Act of 2008 (GINA) protects you—in some cases. It makes it illegal for most health insurers and employers to discriminate based on genetic information, but the law doesn’t cover life insurance, long term-care insurance, or disability insurance.

How’s my genetic information being used?

DTC genetic testing companies may share data for research purposes. James W. Hazel, PhD, JD, a research fellow at the Center for Genetic Privacy and Identity in Community Settings at Vanderbilt University Medical Center, says that the sale of customer data for research is a central part of the DTC business. “The key ethical question is whether the company has provided its consumers with sufficient information and choice,” he says, so that they can make decisions about whether their data may be used in a way that is profitable to the company. “Customers should make an effort to read the fine print.”

This article originally appeared in the June 2020 issue of Health Magazine. Click here to subscribe today!

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