The clinical value of direct-to-consumer (DTC) genetic testing is limited, as the number of genes and genetic variants included in the test are not comprehensive enough to assess risk for most populations and conditions. According to a brief research report published in Annals of Internal Medicine, clinicians should prepare to address and educate patients on their concerns about genetic test results.
The investigators of this case study sought to prepare and guide clinicians to help their patients understand the meaning and limitations of DTC genetic testing. The case scenario describes a young couple planning to start a family who presented their 23andMe results to their provider under the premise that these tests offer information on disease risk and carrier status for autosomal recessive diseases and pathogenic variants with reproductive implications.
However, these tests are limited, including their clinical utility, in which only a fraction of genetic variants contributing to a disease are tested, and in no test does the analysis include comprehensive gene sequencing. These tests are further limited for individuals who are not of European or Ashkenazi Jewish decent, and do not test for variants common in minority populations. In addition, the information from these tests does not account for risk modified by interacting genes, environment, lifestyle, and family history.
The investigators suggest the importance of distinguishing the difference between genetic health risk tests and diagnostic tests. Furthermore, the researchers identified 3 risks related to DTC testing: lack of understanding of the test by the consumer, incorrect test results, and erroneous interpretation of the results. Clinicians should help patients understand the test and its limitations in order to mitigate this risk, and patients who express concern about their genetic test results should be referred to a genetic counselor or qualified provider.
Artin MG, Stiles D, Kiryluk K, Chung WK. Cases in precision medicine: when patients present with direct-to-consumer genetic test results [published online April 20, 2019]. Ann Intern Med. doi: 10.7326/M18-2356