Why genetic testing?

Learn about where your ancestors came from and their ethnicities. Determine whether you are biologically related to another person. Estimate your genetic risk of developing common diseases, such as Alzheimer’s disease. Detect mutations associated with genetic diseases, such as sickle cell anemia or cystic fibrosis. There is a wide range of reasons individuals seek genetic testing, as well as numerous testing options.

Currently, over 175,000 tests are available. The market size has surpassed $14 billion and is expected to reach more than $31 billion by 2027, and over 250 companies are marketing different testing options directly to customers. All of this may leave you wondering about the differences between direct-to-consumer genetic tests (DTC-GTs) and clinical genetic tests (C-GTs).

What are direct-to-consumer genetic tests?

Purchased online or at your local pharmacy, DTC-GTs provide information about your genetic information, such as ancestry, some health traits and health risks, using a saliva sample. You do not need to engage a healthcare professional or use health insurance to cover the cost of DTC-GTs.

What are clinical genetic tests?

C-GTs are ordered by health professionals, such as physicians, nurse practitioners and genetic counselors for a specific medical reason. They are individualized based on your medical and family history and what condition you are being tested for. Results are used to make decisions about your medical care and treatment.

What are the benefits and limitations of direct-to-consumer genetic tests?

While DTC-GTs lack the ability to predict clinical outcomes and are not likely to improve patient outcomes, they may:

  • Offer information to individuals who have no (or limited) information about their family history
  • Provide personalized information about health, disease risk and other traits
  • Help you be more proactive about your health and encourage positive behavior modifications, such as increasing exercise, decreasing cholesterol intake and quitting smoking
  • Provide useful information for medication choice or management
  • Promote awareness of genetic conditions that could have implications for family planning, such as sickle cell anemia and cystic fibrosis
  • Reveal increased risk of an adult-onset disorder, such as hereditary breast and ovarian cancer

Currently, there is little oversight or regulation of DTC-GT companies. Caution should always be exercised when using DTC-GTs and interpreting any results as they:

  • Cannot definitively tell whether you will or will not get a particular disease
  • Provide only partial information about your health and do not take into consideration crucial factors, such as lifestyle choices and family medical history which also affect the likelihood of developing many disorders
  • May reveal unexpected information about your health, family relationships or ancestry that has not been clinically-validated
  • Could lead to additional time and cost if results need to be confirmed with a C-GT
  • May be compromised if testing companies use your genetic information in an unauthorized way or if your data is stolen

You should also consult your physician before making any lifestyle changes based on DTC-GT results.

What are the benefits and limitations of clinical genetic tests?

C-GTs are powerful tools for predicting your risk for future problems, ranging from Alzheimer’s disease to cancer. They allow you to:

  • Be proactive about your health and help determine if family members are at risk of developing certain diseases
  • Make informed reproductive decisions by participating in family planning and prenatal testing during pregnancy
  • Shorten a family member’s diagnostic odyssey, the time between when a symptom or feature of a genetic or rare disease is noted to the time when a final diagnosis is made, by being aware that a genetic condition runs in your family

They also allow your practitioners to:

  • Obtain a clearer portrait of disease risk that can be used to guide medical care and treatment, and lifestyle changes
  • Diagnose genetic conditions, such as cystic fibrosis and Huntington’s disease, unlike DTC-GTs
  • Determine whether the dosage of a medication you are taking is optimal based on how you metabolize that medication

Advances in C-GTs are happening at a rapid pace and continuously improving the ability of practitioners to detect mutations and diagnose disorders. However, C-GTs do have some limitations:

  • Referrals from a clinician are required and not everyone is eligible. For some C-GTs, a family member must already have a disease or disorder and have completed a C-GT for you to get tested too.
  • C-GTs cannot definitively determine if a person will develop symptoms of a genetic condition, how severe the symptoms will be, or how the condition will progress over time.
  • Once diagnosed, many genetic conditions lack treatment strategies.
  • C-GTs can be costly. Prices can range from a few hundred to several thousand dollars.

Want to learn more about genetic testing?

Find the recording of our webinar, “Genetic Testing—Access and Diagnosis, and Direct-to-Consumer vs. Clinical Testing,” where Concert Genetics’ Dr. Gillian Hooker, board-certified genetic counselor and molecular biologist, and I address the genetic testing landscape, access to genetic testing, and the differences between direct-to-consumer and clinical genetic tests here.


SOURCES:

https://assets.kpmg/content/dam/kpmg/xx/pdf/2018/08/direct-to-consumer-genetic-testing.pdf

https://geneticalliance.org.uk/information/service-and-testing/benefits-and-risks-of-genetic-testing/

https://geneticseducation.ca/educational-resources/gec-ko-on-the-run/direct-to-consumer-genetic-testing/

https://healthblog.uofmhealth.org/health-management/pros-and-cons-of-genetic-testing-what-to-know-before-you-go

https://medlineplus.gov/genetics/understanding/dtcgenetictesting/directtoconsumer/#:~:text=Direct%2Dto%2Dconsumer%20genetic%20testing%20provides%20people%20access%20to%20their,for%20a%20variety%20of%20purposes

https://medlineplus.gov/genetics/understanding/dtcgenetictesting/dtcrisksbenefits/#:~:text=Direct%2Dto%2Dconsumer%20genetic%20testing%20promotes%20awareness%20of%20genetic%20diseases,provider%20or%20health%20insurance%20company

https://medlineplus.gov/genetics/understanding/testing/riskslimitations/

https://pubmed.ncbi.nlm.nih.gov/30839387/

https://www.gminsights.com/industry-analysis/direct-to-consumer-dtc-genetic-testing-market