Caring for Carriers: Do Direct-to-Consumer Genetic Test Results Have a Place in Primary Care?
Physicians have a responsibility to help their patients achieve practical health goals, but not to conduct analyses that are not medically indicated.
Now more than ever, patients are receiving their genome sequences right at their doorsteps, with online direct-to-consumer (DTC) genetic testing. Easily accessible ancestry and genetic data, provided by several companies, may seem exciting to recipients at first, but do patients really understand all their results? Are the results even accurate? And should primary care physicians be involved in assessing these results? A case and commentary published in the AMA Journal of Ethics addresses the ethics of physician response and involvement in patient-presented genetic test results.1
A 34-year-old woman brings the results from a DTC DNA testing kit she purchased to her family physician with concerns regarding some of the outcomes. She is heterozygous for the e4 variant in APOE, which is indicative of an increased risk for late-onset Alzheimer disease, and is a carrier of a pathogenic variant in PKHD1, which is associated with autosomal recessive polycystic kidney disease.
The patient asks her physician about her increased risk for Alzheimer disease and about risks of passing autosomal recessive polycystic kidney disease on to her offspring. The physician listens carefully and is provided a copy of the full genetic report, including the second portion that contained extensive genetic information outside the scope of the patient's understanding.
The authors of the fictional case presented here noted that there are several technical and practical issues concerning DTC genetic testing.
Although there are many companies that provide the same general service, not all use the same laboratory protocols, including genotyping machinery or validation techniques.
Authors of a study published in Genetics in Medicine reported that "40% of variants in a variety of genes reported in DTC raw data were false positives."2 In addition, these gene variants were not observed when Sanger sequencing was used to confirm the results.
Laboratory practices adhering to the Clinical Laboratory Improvement Amendments of 1988, the American College of Medical Genetics and Genomics, and the Association for Molecular Pathology can prevent such errors.
The lack of genetic counseling knowledge among physicians was another noted concern. Primary care physicians have the skills to assess history and physical exams, but practices might not necessarily be equipped or proficient in diagnostic or surveillance processes for specific, time-sensitive genetic predispositions.
"If there is a first rule of medicine, it is that physicians should never order a test unless there is a foreseeable benefit from ordering that test," the commentary authors wrote.
Unavoidable risks are associated with any diagnostic test. If the risks outweigh the predicted benefits, it might not be justifiable.
Although it may be easier for physicians to discourage the discussion of DTC genetic testing results or products with patients, it is in the patient's best interest for physicians to educate themselves on the different testing kits available to consumers, and to answer product-related questions in a respectful way. Not only does this encourage patient-physician interaction, but it also helps build trust.
Claims associated with certain genetic variants are constantly fluctuating. It is important for primary care physicians to assess what they do and do not know about genetic testing. Even for physicians who educate themselves in DTC genetic testing, the authors suggest referring patients to specialists who can further analyze patient genetic results.
"Deciding upon a course of action will fall to individual patients and physicians," the commentary authors concluded. "Shared decision making does not, however, mean that primary care physicians should order any test a patient wants. Shared decision making is about seriously engaging in conversation together so that physicians understand their patients' unique circumstances and concerns and so patients have opportunities to benefit from their clinicians' expertise."
Disclosure: All authors of the study published in Genetics in Medicine are full-time employees of Ambry Genetics Corporation.
- Brothers KB, Knapp EE. How should primary care physicians respond to direct-to-consumer genetic test results? AMA J Ethics. 2018;20(9):E812-E818.
- Tandy-Connor S, Guiltinan J, Krempely K, et al. False-positive results released by direct-to-consumer genetic tests highlight the importance of clinical confirmation testing for appropriate patient care [published online March 22, 2018]. Genet Med. doi: 10.1038/gim.2018.38