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6 things you should know about genetic testing

Thanks to modern medicine, we have more than 7,000 genetic tests that can potentially identify red flags for certain diseases. Genetic testing is not perfect — it can’t guarantee answers to all our health questions — but it’s a useful tool that can help arm us with information to consider when making health-related decisions.

There are a few things you should keep in mind before undergoing genetic testing. Multiple types of genetic tests exist, but here we will focus on next-generation sequencing, which is a new method for examining genomes that’s used by many hospital and commercial labs for diagnosis, prognosis and possible drug selection.

It’s important to note that this kind of testing is different than the direct-to-consumer DNA testing for ancestry and some health information, since those tests don’t examine all the relevant parts of the gene for specific diseases determined by your medical and family history.

You and your healthcare provider can determine if genetic testing is the right answer for you, as well as what type of testing is appropriate. Here are six things to consider beforehand:

1. Genetic testing is one of many tools 

The test result is interpreted with knowledge of your clinical condition, family history and medical history. You may have a positive result, a negative result or a result of uncertain significance. A positive result reveals a gene mutation or a change in the DNA sequence that makes up a gene. Having this knowledge may give you the opportunity to be proactive with your healthcare.

Write down your questions about any test results and share them with your healthcare provider. Your provider can answer as many questions as possible and may refer you to a genetics professional.

A genetics professional specializes in genetic testing and is often the most qualified individual to help with the interpretation of your results. Just as an orthopedist is specially trained to treat bone and joint issues, a geneticist has special training regarding genetic disorders, testing and interpretation of results.

2. A negative result doesn’t always mean no mutation

Genetic tests can look for a specific change within a single gene, multiple changes within a gene, multiple genes or the majority of your genetic material. The type of testing is determined by a number of factors, such as your medical condition and family history.

But it’s important to remember that a negative result does not always mean there is no mutation present. There are twenty thousand genes and there are spaces in between the genes that are not always tested. A negative result might prove you don’t have a specific disorder or predisposition to a disorder, or it is possible that the gene responsible for the condition was simply not tested.

For the most information, it is important to test a family member that actually has the condition you’re testing for. That way, if the person is positive and you are negative, it is a true negative. If, however, that person is negative, then the test is currently uninformative and other family members should not be tested.

3. A result of uncertain significance is similar to not having a result at all

A result of uncertain significance means that there was a change in the gene, but we do not have enough information to know the meaning of that change — it’s not positive and it’s not negative.

As more information is gathered on these changes, most of these result as negative, but some do turn out to be positive. In this case, it may be helpful to test other family members with and without the disease, or to test parents. No medical changes should be made based on a result of uncertain significance.

4. The results have a greater impact than you may think

Sometimes, the results may affect more than just you — they may impact other family members, too. It may be important for you to inform other family members of your results. Sometimes results can be unexpected, and it’s important to prepare for next steps.

If you receive a positive test result for an untreatable cancer or disease, how might you handle that news? Are you comfortable sharing that information with your family? How would they feel about hearing the results? What preparations would you make? Think through the implications of each scenario.

5. Genetic tests can be expensive 

Sequencing of genes might not be covered by insurance, or the testing company performing the test could be out of your provider’s network. It is important to talk to your insurance provider to see the costs of testing, whether labs are in-network, and to what extent genetic counseling might be covered.

6. Genetic counseling is an important step

Any type of genetic testing can be complex, and the results can be difficult to interpret, but genetic counselors or MD geneticists will walk you through every step so that you can make an informed decision.

Genetic counselors and MD geneticists are trained to explain the pros and cons of undergoing testing versus not testing, and will suggest tests based on your ancestry, family history and clinical conditions. They’ll help decipher what the results mean and guide you through the next steps.

Both the clinical genetics division and the genetic laboratories at Baylor Scott & White Health are resources for making sure you receive the correct genetic test ordered for your particular circumstance by your physician.

Even with more than 7,000 available genetic tests, there are still many unknown gene mutations and gene effects for various diseases. Genetic testing is at the forefront of modern medicine, and with time, the number of tests and options available will increase. While these tests equip us with information to help us make informed decisions about our healthcare, it is important to consider all factors associated with the tests.

If you’re considering genetic testing, be sure to take the proper steps. Find out more about genetic testing and genetic counseling at Baylor Scott & White Health.

About the author

Sheila Dobin, PhD
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Dr. Sheila Dobin is a board-certified cytogeneticist and PhD Medical Geneticist on the medical staff at Scott & White Medical Center – Temple. She is currently the section chief of the Cytogenetics Laboratory in the Department of Pathology at Scott & White Medical Center – Temple and in the Division of Genetics in the Department of Internal Medicine.

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6 things you should know about genetic testing