Posted by & filed under Direct-to-Consumer DNA Testing, Genetics as Preventative Care, Rare Disease.

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Five key points to help you decide

There are many things to consider when deciding whether or not to proceed with online genetic testing or not.  Unlike other health screens such as checking your blood pressure, or bone density, knowing your genetic carrier status can alter your own self-perception.  There are many considerations that should go into carefully deciding whether genetic testing is right for you, and whether now is a good time to pursue testing.  This post aims to provide you with some guidelines, but it cannot possibly replace care from a trained genetics professional.

1. Is this the right time in your life?

We do not recommend having genetic testing performed during times of unusual stress or duress.  For example, getting screened while preparing for a wedding, or while facing a layoff from work are NOT ideal times to pursue genetic testing.  Ideally, you should feel like you are in a good place in life, and have plenty of social support.

2. How is this genetic test significant and important to your health?

Some DNA tests have a greater impact on your health management than others.  How important is this test to your health?  For example, finding out you have inherited a variant in the BRCA1 gene changes your medical care dramatically.  Thankfully there are many courses of action we can take to prevent breast and ovarian cancers for those who carry these variants.  Meanwhile, finding out you have a variant in an APOE gene that is associated with Alzheimer’s disease does not change your course in treatment–with the exception being that you can make important lifestyle changes.  Are you at high risk due to a family history, or maybe because of your ethnicity?  Are there treatments available to people who have the condition?  How do you feel about having this disease or having a child with this disease?  By answering these questions for yourself, you can start to weigh the benefits of the test to the risks (#4, below).

3. How can you determine the quality of the test that’s offered?

No two genetic tests are created equal.  Assessing the quality of a test is something that genetic counselors are most proficient at, but here are some basic tips:

Inquire with the testing company about the “detection rate” for your particular ethnicity.  No single genetic test is able to pick up 100% of the variants, mutations, rearrangements that can be found.  It is important to know what are the chances that this test may miss something, giving you a false sense of security.

On the flip side, if the lab detects a variant in you, then what is the likelihood that it may cause the disease it is associate with?  In technical terms, we call this the positive predictive value.  Simply having a variant in a particular gene does NOT guarantee that you will be facing that disease during your lifetime.  It is crucial that you find out what having a variant implies to your health and wellness.

Lastly, what is the chance of getting a “VUS” or a variant of uncertain significance.  The lab should be able to inform you how frequently this happens. (See #5 below for more details).

4. What risks might you be facing by pursuing this test?

There are many risks to consider prior to proceeding with a genetic test, as such this list cannot be exhaustive.  Genetic discrimination is rare, but a real risk.  If the genetic test is predictive in nature, and can inform you the chances of your getting a disease (Huntington’s disease, or breast cancer are examples) then it is highly recommended that you consider long term care insurance and life insurance policies prior to testing.

One of the biggest concerns healthcare providers have for DTC genetic testing is that the interpretation is left up to you.  If you are not provided with important information involving your medical management, key life-saving screenings can go missing.

Another concern is that you may be surprised by ancillary findings.  So, for example you might have ordered a test simply to learn about pharmacogenetics that will help you to predict your ability to metabolize medications.  But in addition to learning about your pharmacogenetic profile, you also are surprised to learn that you have a mutation in a completely unrelated gene, predisposing you to a different genetic condition.  The chance of uncovering ancillary findings varies from test to test, lab to lab, so it is worth inquiring about.  The Whitehouse assembled a taskforce to discuss the issue, you can read about their conclusions at greater detail here: Ethical Management of Incidental and Secondary Findings in the Clinical, Research, and Direct-to-Consumer Contexts (Dec 2013).

5. What will you do with the results?

If the results are positive (they find a variant in a disease gene), you may consider:

  • Getting healthcare providers involved.  What can your genetic counselor or physician inform you?
  • Informing family members–anyone who might also benefit from getting the test performed.
  • Paying close attention to changes in your health recommendations, based on the results.  Changes to your diet, incorporating additional screenings, or prophylactic treatments might initially sound overwhelming but they can be important considerations and may save your life.
  • Investigating if there are prenatal tests so you can avoid passing disease on to your children.  If so, will your partner (or donor) also need to be screened?

If the results are negative (no variant is detected in the disease gene):

  • Ask how confident the lab is in this result.  Again, no test is 100% accurate, so what is the ‘residual risk’ that you are still a carrier?  This risk is typically related to your ethnicity.
  • You can feel somewhat confident that you are not a carrier, if the testing is done correctly.

If the results are inconclusive (a variant was detected, but the lab was unable to interpret its meaning):

  • This may or may not apply to the type of testing you are pursuing.  A trained genetics professional can help you better understand the significance of your result.
  • Will the lab inform you of these results?  Note that not all labs report inconclusive variants.
  • Interpretations of variants can change as time goes on, and we have more data available.  How often can you find out if a variant has been reclassified?  Will you need to contact the lab, or will they reach out to you?

How can I make a decision about DTC genetic testing?

We realize deciding about online genetic testing can be a bit overwhelming.  We also acknowledge that genetic testing is not for everyone.  For some people, the answer is clear, and they can proceed with our without testing.  If things remain unclear, try listing the pros against the cons.  Which list is longer?  However if questions persist we recommend you speak with your clinical genetic counselor or other genetic health provider.  If you don’t have access to a clincal genetic counselor, you can contact Vibrant Gene, or visit nsgc.org to locate one.

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