The Universe of Genetic Testing

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Pros and Cons of Clinical Genetic Testing

Genetic testing holds great potential for the future of medical care. It offers many benefits, including providing important information that can be used when making decisions about having a family and taking care of one's own health. However, there are also limitations. For this reason, it is important to understand the nature of genetic testing and the information that it can and can't provide. For example:

  • Clinical genetic tests are not just descriptive as many laboratory tests are (such as describing the glucose level in your blood), but they are predictive as well. Predictive tests will not give a yes/no answer, but instead will tell what the chances are of developing a particular genetic condition. Such results are not definitive and may leave a person wondering what to do with those results, particularly if available treatments or therapies limit the course of action.
  • A particular genetic test will only tell if there is specific genetic variant, or mutation; it cannot guarantee whether the disease will develop nor can the test provide information about other genetic diseases not being specifically looked for by that test.
  • While the test may detect a particular problem gene, it cannot predict how severely the person carrying that gene will be affected. Again with cystic fibrosis, symptoms may be mild bronchial abnormalities or they may range to severe lung, pancreatic, and intestinal problems depending on the specific mutation present.
  • Many genetic tests cannot detect all of the variations that can cause a particular disease. For instance, with genetic testing for cystic fibrosis, most genetic testing panels only look for the more common variants, not all of those that are associated with this disease.
  • Many diseases are the result of an interaction between one's genes and one's environment. The way in which these interactions cause disease is not clearly understood. Examples of these diseases include coronary heart disease, type 2 diabetes, obesity, and Alzheimer disease.
  • Legal issues, such as patient privacy, use of genetic testing to determine insurance coverage, and the use of archived patient samples are some of the broader social issues to be considered.

Because of these limitations, genetic test results can be a mixed blessing. An absolutely essential component of clinical genetics testing is giving your informed consent to do the tests and knowing what you want to do with the results of these tests. Know your legal rights as well. Make certain that your privacy is respected. Educate yourself about genetic tests, and talk to your medical provider if you think you should have genetic testing performed. This is especially important as more genetic testing becomes available directly to consumers. For more on this, listen to the following podcast from Clinical Chemistry and watch the NOVA program,  Cracking Your Genetic Code.

Direct-to-Consumer Genotyping (Clinical Chemistry, August 2010)

It is also important to remember that genetic testing is different from other types of laboratory testing. Results of genetic tests may have implications not only for you the patient, but also for your family members, who may need to be tested as well. In addition, genetic education and counseling is often advised to help understand and cope with the results of genetic tests. Genetic counselors are trained professionals who can help those with family members who have a genetic disorder as well as those at risk to better understand the science behind inherited conditions. They can identify families at risk of certain genetic disorders and offer support and counseling as well as serve as patient advocates. For more information on genetic counselors and to find one near you, visit the National Society of Genetic Counselors web site.

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