Genetic testing: Answers to your questions

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  • Kristen Yu

    Kristen Yu

 
By NorthShore University HealthSystem

Stories in the news about inaccurate genetic testing results leading to misdiagnosis may leave patients concerned about how accurate the testing is and how it works.

So, we've asked Kristen Yu, who provides genetic counseling through NorthShore to adults diagnosed with or at risk for various conditions, including hereditary cancer syndromes, to answer some questions about genetic testing.

Q: How do genetic counselors help guide patients through genetic testing results?

A: Genetic counselors play an important role in helping patients understand what information their genetic testing evaluated and how to understand, interpret and potentially act on that information.

If any "pathogenic variants" (also called mutations) were identified, we provide information about what that result means for the patient, including any disease risks, management options, and implications for family members. We also make sure to get patients connected with any specialists or resources that will help with their care going forward.

Even if no variants are identified on a genetic test, genetic counseling can be helpful for a patient to understand any remaining risks and to determine if additional testing or screening is appropriate. In some instances, another family member may be the best candidate for genetic testing to help the family understand risk.

Q: What does a typical session look like, what can the patient expect?

A: We ask patients questions about their personal and family history, and analyze this to provide a personalized risk assessment.

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Based on this information, we can offer genetic testing options tailored to their history and personal preferences, and help determine if testing is the right choice for them.

We also help patients who have already had testing understand the meaning of their results and next steps.

Another important part of our service is helping patients navigate the psychosocial impact of genetic diseases and/or test results, such as how they may react to learning about their genetic information, how they can communicate this information to relatives, and how to connect to support resources.

Q: What are considered "positive" results/"negative" results?

A: Understanding the difference between "positive" results and "negative" results in testing is important, and not always intuitive for patients.

There are different types of positive results (often called a "pathogenic variant" or "mutation"). In some situations, a positive result may diagnose a disease. Other times, the result indicates an increased risk to develop a disease, but does not mean that disease will definitely develop.

                                                                                                                                                                                                                       
 

Some positive results don't cause any health issues for the patient, but can have implications for children if the patient's partner also has a pathogenic variant in the same gene.

A negative result means that no genetic variants were identified on the test ordered. However, there can be other factors that may increase risk for certain diseases based on personal history, family history, or other risk factors.

There is no one genetic test that can rule out all genetic susceptibilities.

Occasionally patients may have a "variant of uncertain significance" identified on their testing. This is a change in a gene that we do not have enough information about to know whether it causes an increased risk for a disease, or whether it is a benign change not associated with disease risk.

In most cases these uncertain variants should not be used to make management decisions, and patients should stay in touch with their genetics provider to learn of any updates.

                                                                                                                                                                                                                       
 

Q: What are some of the most frequently asked questions that patients have?

A: Patients frequently want to know how genetic test results can be used to prevent diseases or change management recommendations.

Another common question is how family history or genetic test results impact risk for other family members, like children.

Some patients have questions about the potential for discrimination related to genetic testing, and we provide education about protections such as the Genetic Information Nondiscrimination Act.

Q: How do you determine a recommendation for a patient to be "retested"?

A: Patients who have genetic testing through a direct-to-consumer company or as part of a research study typically require retesting through a clinical grade laboratory before using those results to impact their care.

Meeting with a genetic counselor can be helpful to determine if retesting is needed and to facilitate the process.

Patients who are tested at reputable clinical laboratories typically do not require "retesting" at the time of their results. However, as we learn of new genes or develop improvements to genetic testing technologies, patients may be candidates for updated genetic testing in the future.

If there is a change in their personal or family history, additional genetic testing may also be recommended. For this reason we recommend patients check in with their genetics provider every few years to see if they would benefit from an updated evaluation.

Q: How do you work with the physician teams when referring patients to specialists?

A: The Mark R. Neaman Center for Personalized Medicine has specialists who manage patients with specific genetic conditions, including predispositions cancers and heart diseases. Our genetic counselors help connect patients to the appropriate specialist to create a management plan, and we are always available to consult with a patient's care team to make sure they are getting comprehensive care.

Q: Can you provide me with a "generic" example of how you have helped a particular patient navigate their results and recommend "next steps"?

A: We see many patients for evaluation due to a family history of breast or prostate cancer.

For example, if a patient tests positive for a pathogenic variant (i.e. the BRCA2 gene), we educate him/her about the increased risks associated with that gene, and recommended and next steps. We assist in referring to appropriate specialists to discuss management options, such as Dr. Allison DePersia in the High Risk Breast Clinic (to discuss options such as breast MRI, chemoprevention, prophylactic mastectomy) or Dr. Brian Helfand in the Personalized Medicine- Prostate Clinic (to discuss PSA screening and biopsy recommendations).

We also identify which family members would benefit from genetic testing based on this result, and connect patients with resources they might find helpful, such as FORCE.

• Kristen Yu earned her Master of Science degree in Human Genetics and Genetic Counseling from Stanford University in 2013, and has been board certified with the American Board of Genetic Counseling since 2013. At NorthShore she provides genetic counseling to adults diagnosed with or at risk for various conditions, including hereditary cancer syndromes. She also has experience providing counseling for rare tumor predisposition syndromes and hereditary cardiac diseases. She is involved with various research initiatives through NorthShore's Department of Personalized Medicine, including the Genomic Health Initiative. Kristen also enjoys teaching and supervising Northwestern genetic counseling students.

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