Genetic testing becomes a very common practice among the consumers. We can have our genetic makeup determined by various tests, starting at $99 and going up to $5000 or more per test. The quality of the tests varies, and information delivered is different. What can we find out from the test:
- a carrier status test for selected mutations in about 90 to 120 genes,
- risk factors for a number of conditions (breast cancer, cardiovascular disease, Alzheimer’s and others),
- our ancestry
- find the best nutritional choices
- find the custom cosmetic choices
- and more
What really can the tests deliver? What do those reports mean? The reports give you an information that a particular variant of a gene was found or not found in your sample.
Are any of the tests exhaustive, do they give us all the information? Are they 100% accurate? No, they provide only information that they can based on how they were designed and our current understanding of genetics and gene regulation. The tests are accurate in delivering a good result but as to predicting what the result means they are not always so accurate.
Genetic counselors caution consumers about unknown value of some of the tests for cancer, macular degeneration, asthma, arthritis, diabetes or cardiovascular risks. There is an undisputed genetic component to those conditions but this is only one side of the coin. Environmental factors can have an important contribution to the final manifestation of the disease, as can mutations in other genes so far not associated with a particular disease. It will take some more research before we can easily and with some assurance correlate genotype and environmental factors.
Obvious question then arises in everyone’s mind – should I get tested or not? Is it worth the money? You need to consider why you want to get tested. If you want to determine your carrier status for common genetic diseases because you consider pregnancy, then yes you should but talk to your doctor or genetic counselor to pick the best test for you. If you want to know anything about your risk factors for particular diseases, then definitely talk to a genetic counselor. They can suggest what tests would be useful, what are their limitations and value for you.
The FDA cautioned some of the companies providing direct to customer genetic testing and since then the companies employed their own genetic counselors. However, you should look for advice before sending your sample not just after you get your report. That way you will understand what expectations you can have from the test and what do to when you get your report or elect the report to go to the counselor instead. Some studies shown that people handled the information in those reports well, but you never know how you will react to news of increased risk of developing Alzheimer’s or Huntington’s disease. Obviously risks to diseases like diabetes or cardiovascular disease are easier to handle and we all feel like we can do something about the risk. However, even in those cases you should get medical advice and more testing to ensure that prevention will work well.
It is very important to understand that a genetic test is only one side of a coin, environment is the other and our understanding how the two affect each other is imperfect and incomplete. Risks factors reported based on the test are probabilities only, they do not mean you will have a disease.
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