Is it a good thing or a bad thing when laypeople are able to order their own genetic profiles and interpret their own results, sometimes without the guidance of trained health-care personnel or a genetics counselor?
For many years, clinicians have had the ability to conduct genetic tests, which can be used to determine, for example, how likely a person is to pass along a disorder based on a single faulty gene, such as phenylketonuria (PKU). Genomic tests, by contrast, are part of a growing field that examines all genes and their interrelationships. Genomic tests are used to identify the combined influence these interrelationships have on the growth and development of an organism, according to the World Health Organization .
Direct-to-consumer (DTC) genetic and genomic test kits generally are advertised on the Internet, often are ordered without input from a health-care provider, and may produce results that range widely in terms of clinical validity and utility, even when the test comes from a reputable lab. Because many diseases involve complex interactions between genetics and environment, it is misleading for manufacturers of DTC tests to imply that possessing a certain genetic profile is the only factor that matters.
Furthermore, even if knowing that a person is genetically predisposed to a particular disease might lead to early detection, this information is not necessarily beneficial if there is no available preventive intervention or early treatment to alter prognosis.
DTC genetic testing also may carry substantial tangible and intangible costs for individuals, as well as for society, due to false-positive or false-negative results. A woman who thinks she is not at risk for breast cancer may not go for mammograms, whereas one who thinks she is at increased risk may demand invasive tests or procedures, and could suffer unfounded emotional distress.
In 2010, the U.S. Government Accountability Office reported on a year-long undercover investigation of DTC genetic-testing firms, finding “egregious examples” of deceptive marketing, poor posttest counseling and results that were “misleading, and of little or no practical use” overall.
However, we should also recognize that DTC genetic testing can promote prevention by allowing us to encourage the patient to make lifestyle changes based upon risks discovered in this process. These tests can also help us discover biomarkers and tailor therapies to a person’s specific genetic profile.
We can only hope that DTC genetic testing becomes more sophisticated, more clinically useful and better regulated. It is likely that this practice will become more mainstream, so it’s important that we educate ourselves in matters related to DTC genetic testing so that we can help patients who turn to us for interpretation and support.
Clinicians should be prepared to explain the following:
- What a particular test can and cannot predict and its degree of accuracy
- The psychological and physical implications of a positive or negative result
- Confidentiality issues, and their association with the risks of insurance or employment discrimination
- The effects on others, such as children or other at-risk relatives who now possess information they may not have wanted in the first place.
Judi Greif, RN, MS, APNC, is a family nurse practitioner and medical writer currently residing in East Brunswick, N.J.