Editors' ChoiceHuman Genomics

Genetic Testing Exonerated

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Science Translational Medicine  09 Feb 2011:
Vol. 3, Issue 69, pp. 69ec16
DOI: 10.1126/scitranslmed.3002177

Over the last 5 years, more than 800 DNA variants in the human genome have been tied to susceptibility to developing different diseases. These findings have spawned a new era in genetic testing in which companies are marketing direct-to-consumer (DTC) genome-wide profiling kits to enable the general public to assess their own disease risk. However, there are concerns about the clinical value of the DNA variants tested by these kits, the potential for anxiety induced by the test results, and the possibility that individuals will seek unnecessary medical treatments on the basis of the test results. Such concerns have prompted calls for widespread regulation of the DTC genetic testing industry.

A new study by Bloss et al. suggests that some of these concerns may be overblown. These investigators assessed psychological, behavioral, and clinical effects in more than 2000 healthy volunteers who underwent DTC genetic testing with a commercially available kit. All study subjects received a baseline health assessment using a Web-based survey and a follow-up about 5 to 6 months after taking the genetic test. At follow-up, the investigators found no significant association between disease risk as indicated by the genetic test and anxiety, dietary fat intake, or exercise behavior. However, the 25% of study subjects who showed their results to their physicians did display a significant decrease in fat intake. Further, although there was a statistical link between the composite risk for disease and the intention to undergo additional medical screening, the actual proportion of individuals who completed the medical screening did not differ between the groups.

Overall, these data suggest that there are minimal downsides to DTC genome-wide profiling for disease risk. However, several critical aspects of the study preclude extrapolation of the findings to the general population. First and foremost, only 44% of the patients who enrolled for the study completed the follow-up portion. Second, the short duration of the follow-up period limits the ability of the study to speak to the long-term effects of DTC genetic testing. And third, the cohort studied was a highly educated and financially well-off population. As testing becomes more affordable and physicians begin to leverage genomic information in their practices, a much broader population will begin to receive DTC genetic tests, and the effects of testing may be different to those seen in the current study. Nevertheless, direct-to-consumer genome-wide profiling to assess disease risk is here to stay and is likely to become much more common.

C. S. Bloss et al., Effect of direct-to-consumer genomewide profiling to assess disease risk. N. Engl. J. Med. 12 January 2011 (10.1056/NEJMoa1011893). [Abstract]

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