Privacy issues aside, as an attorney I immediately wonder about the risks of arming the everyday consumer with genetic information without counseling from a clinician or genetic counselor. I immediately think of the experience of Francis S. Collins, a well known pioneer of personalized medicine. In his book, "The Language of Life: DNA and the Revolution in Personalized Medicine," Dr. Collins submitted his DNA sample to three companies: 23andMe, deCode and Navigenics. While the genetic variant results that all three companies tested were the same, sometimes the interpretation of what to do with those results were shockingly different!!
23andMe and deCode looked at the exact same DNA variants related to the metabolism of Coumadin, a common blood thinner. 23andMe reported "increased sensitivity" indicating that his dose should be adjusted downward to avoid toxicity, while deCode suggested he would only need an "average dose." Same test, different interpretation, what gives? Without the complete patient and family history-how can you make a blanket statement that he would need an average dose? There are several clinical factors that are involved in prescribing Coumadin that should be taken into consideration before changing a dose based solely on genetic information. What if the consumer took the suggestion of an average, increased or reduced dose literally without consulting their doctor? The results could be tragic.
When looking at Dr. Collin's risk for prostate cancer, 23andMe suggested lower than average risk, deCode suggested a slightly elevated risk and Navigenics predicted a risk of 24% compared to the baseline risk of 17% for most men. Why was this? As it turned out, 23andMe only tested for 5 variants known to affect prostate cancer risk, deCode had tested 13 and Navigenics had tested 9. No company tested the complete set of 16. Lucky for Dr. Collins, as a trained practitioner with genetic knowledge, he was able to look at the entire data set of genetic variants and determine that he probably should be paying closer attention to his prostate cancer risk than the average man, including testing and preventative measures. If he had taken the 23andMe test result at face value, he may have ignored his higher risk condition. This could easily happen to the average consumer when looking at risk predictions for developing diseases from tests that do not provide the entire data set necessary to assess that risk.
These are just two very simple examples of how direct-to-consumer genetic testing has serious pitfalls. Predictions for ancestry and non-medical traits contained on these reports, such as ability to taste bitter foods, is entertaining. Yet, even Dr. Collins noted that while 23andMe predicted he would have brown eyes, he definitely has blue eyes!
The bottom line is this: Consumers may use the information on these reports to make medical decisions without even consulting a medical professional!
In this attorney's opinion, that's bad for the medical profession, consumers and the future of personalized medicine. My sincere recommendation is to always have genetic testing for medical traits ordered through your physician's office after they determine it is medically necessary. Further, make sure your physician is able to interpret and recommend a course of action based not only on your genetic variants but with taking into consideration your entire medical and family history. If your physician is not savvy on genetic testing, please suggest they seek some continuing medical education on the subject.
Geneticational, LLP is currently providing public speaking events and educational seminars on genetics in personalized medicine and will be offering educational and course materials through its website in the near future. Your physician and/or the physician practice group may request information on seminars and courses offered (some for CME credit) by submitting an information request through www.geneticational.com.
No comments:
Post a Comment