Hype or Help? The Truth About Genetic Testing

If one test could shed light on your past and your future, would you take it? Genetic testing can help people do just this, offering insight into family history and health.

Based on industry estimates, about 1 in 25 American adults have taken advantage of this theoretical “crystal ball” and now have access to their own genetic data.

According to the National Human Genome Research Institute, genetic testing is a medical test that looks at your DNA, which you inherit from your mother and your father. Genetic tests may be used to identify increased risks of health problems, to choose treatments or to assess responses to treatments. More than 80,000 genetic tests are available through health care providers. Many at-home genetic tests are also available directly to consumers, using gene variations to make predictions about health, provide information about common traits and offer clues about a person’s ancestry.

Should I get tested?

There are many medical reasons for getting a genetic test. Dr. Jennifer Malin, UnitedHealthcare Senior Medical Director of Oncology and Genetics, said common scenarios include:

  • When someone has symptoms of a genetic disorder, such as Huntington’s Disease, a test can help with diagnosis.
  • Pregnant women can learn whether they carry a recessive condition like cystic fibrosis.
  • Babies can be tested in utero for non-hereditary genetic mutations like the one that causes Down syndrome.
  • People with a family history of certain cancers, including breast, ovarian or colon cancer, can be tested to see if they are genetically predisposed to that cancer.

While tests can be done to determine if you have a genetic risk for a disease, such as Alzheimer’s disease or heart failure, it’s important to consider how actionable this information will be. For example, a genetic test for breast cancer can prompt earlier or more frequent disease screening, but not all tests have such a clear course of action.

“For many of the tests that are being marketed, there isn’t necessarily anything yet we can do with the information,” Dr. Malin said. “There are tests that are being marketed to determine whether or not the dosing of drugs should be adjusted. But we don’t really have the medical science to know how to adjust drugs based on these tests, so the information might end up having a negative impact on your care.”

Dr. Malin recommends engaging a genetic counselor. They help patients and providers chose the right genes to test, select an accurate lab, interpret and use the results effectively.

While our genes play a role in what disease we may develop, keep in mind that they are not the whole story. For example, only 5 to 10 percent of all cancers are thought to be caused by genetic mutations; the majority of cancers are caused by diet and lifestyle choices such as smoking. Given all the other factors at play, a positive result on a genetic test for a particular disease does not always mean you will develop it, nor does a negative result mean you won’t. A genetic counselor can explain what a test will or will not tell you.

What kind of test should I use?

Why go through the trouble of getting a doctor and genetic counselor to help you with a test when you can get a kit through the mail and take it at home?

“Direct-to-consumer tests might be fun for learning about your ancestry, but they are not a substitute for medical tests,” said Dr. Malin. She noted that a new study shows commercial tests are wrong 40 percent of the time when it comes to disease prediction.

They also are limited in scope, as they don’t test for all genes. Dr. Malin offers an example of the limitations of the tests: “One company is now testing for mutations in the two genes related to breast cancer, but only for the three most common mutations on those two genes, not all of them. So even if you get a negative result, that doesn’t mean you’re in the clear.”

How do I get tested?

If you think a genetic test is warranted, talk with one of your health care providers, who often can order the tests through their clinics or can connect you with a genetic counselor to help interpret results.

Be sure to ask questions upfront. “You will want to select a reputable lab and ensure that you’re being tested for the genes that are of greatest interest to you,” Dr. Malin said.

You also might want to check with your insurance carrier to see whether the test you are interested in is covered.

Understanding more about your genetic makeup may help you better identify your disease risks and plan for ways to decrease your chance of getting certain diseases. In the future, a genetic test may become a standard part of your annual check-up with your doctor, to get a better understanding of your health status and make lifestyle changes to stay well.