Direct-to-consumer (DTC) genetic testing refers to genetic tests that are marketed directly to consumers via television, print advertisements, or the Internet. This form of testing, which is also known as at-home genetic testing, provides access to a person’s genetic information without necessarily involving a doctor or insurance company in the process. [definition from NLM's Genetic Home Reference Handbook]
Almost two years ago I wrote about 23andMe (23andMe: 23notMe, not yet), a well known DTC company, that offers a genetics scan (SNP-genotyping) to the public ‘for research’, ‘for education’ and ‘for fun’:
“Formally 23andMe denies there is a diagnostic purpose (in part, surely, because the company doesn’t want to antagonize the FDA, which strictly regulates diagnostic testing for disease). However, 23andme does give information on your risk profile for certain diseases, including Parkinson”
In another post Personalized Genetics: Too Soon, Too Little? I summarized an editorial by Ioannides on the topic. His (and my) conclusion was that “the promise of personalized genetic prediction may be exaggerated and premature”. The most important issue is that predictive power to individualize risks is relatively weak. Ioannidis emphasized that despite the poor evidence, direct to consumer genetic testing has already begun and is here to stay. He proposed several safeguards, including transparent and thorough reporting, unbiased continuous synthesis and grading of the evidence and alerting the public that most genetic tests have not yet been shown to be clinically useful.
And now these “precautionary measures” actually seem to happen.
Last week the FDA sent 5 DTC-companies, including 23andMe a letter saying “their tests are medical devices that must receive regulatory approval before they can be marketed.” (ie. see NY-times article).
Alberto Gutierrez, who leads diagnostic test regulation at the FDA, wrote in the letters:
“Premarket review allows for an independent and unbiased assessment of a diagnostic test’s ability to generate test results that can reliably be used to support good health care decisions,”
These letters are part of an initiative to better explain the FDA’s actions by providing information that supports clinical medicine, biomedical innovation, and public health,” (May 19 New England Journal of Medicine commentary, source: see AMED-news)
Although it doesn’t look like the tests will be taken from the market, 23andMe does take a quite a rebellious attitude: one of its directors called the FDA “appallingly paternalistic.”
Many support this view: “people have the right to know their own genetic make-up”, so to say. Furthermore as discussed above, 23andMe denies that their genetic scans are meant for diagnosis.
In my view the latter is largely untrue. At least 23andMe suggests that knowing a scan does tell you something about your risks for certain diseases.
However, the risks are often not that straightforward. You just can’t “measure” the risk of a multifactorial disease like diabetes by “scanning” a few weakly predisposing genes. Often the results are given in relative risk, which is highly confusing. In her TED-talk the 23andMe director Anne Wojcicki said her husband Sergey Brin (Google), had a 50% chance of getting Parkinson, but his relative risk (RR, based on the LRRK2-mutation, which isn’t the most crucial gene for getting Parkinson) varies from 20% to 80% , which means that this mutation increases his absolute risk of getting Parkinson from 2-5% (normal chance) to 4-10% at the most. (see this post).
Furthermore, as reported by Venture in Nature (October 8, 2009): For seven diseases, 50% or less of the predictions of two companies agreed across five individuals (i.e. for one disease: 23andMe : RR 4.02, and Navigenics RR: 1.25). On the other hand *fun* diagnoses could lead to serious concern in, or wrong/unnecessary decisions (removal of ovaries, changing drug doses) by patients.
There are also concerns with regard to their good-practice standards, as 23andMe just flipped a 96-wells plate of costumer DNA (see Genetic Future for a balanced post), which upset a mother noticing that her son didn’t have compatible genes. But lets assume that proper precautions will prevent this to happen again.
There are also positive aspects: results of a preliminary study showed that people who find out they have high genetic risk for cardiovascular disease are more likely to change their diet and exercise patterns than are those who learn they have a high risk from family history. (Technology Review: Genetic Testing Can Change Behavior).
Furthermore, people buy those tests themselves and, indeed, there genes are their own.
However, I agree with Dr. Gutierrez of the FDA saying: “We really don’t have any issues with denying people information. We just want to make sure the information they are given is correct.” (NY-Times). The FDA is putting the consumers first.
However, it will be very difficult to be consistent. What about total body scans in normal healthy people, detecting innocent incidentilomas? Or what about the controversial XMRV-tests offered by the Whittemore Peterson Institute (WPI) directly to CFS- patients? (see these posts) And one step further (although not in the diagnostic field): the ineffective CAM/homeopathic products sold over the counter?
I wouldn’t mind if these tests/products would be held up to the light. Consumers should not be misled by the results of unproven or invalid tests, and where needed should be offered the guidance of a healthcare provider.
But if tests are valid and risk predictions correct, it is up to the “consumer” if he/she wants to purchase such a test.
“What Five FDA Letters Mean for the Future of DTC Genetic Testing” at Genomics law Report is highly recommendable, but couldn’t be accessed while writing the post.
[Added: 2010-06-14 13.10]
- Problem assessing Genomics Law Report is resolved.
- Also recommendable: the post “FDA to regulate genetic tests as “devices”” at PHG Foundation. This post highlights that simply trying to classify the complete genomic testing service as “a device” is inadequate and will not address the difficult issues at hand. One of the biggest issues is that, while classifying DTC genetics tests as devices is certainly appropriate for assessing their analytical validity and direct safety, it does not and cannot provide an assessment of the service, thus of the predictions and interpretations resulting from the genome scans. Although standard medical testing has traditionally been overseen by professional medical bodies, the current genomic risk profiling tests are simply not good enough to be used by health care services. (see post)