In November 2013, the U.S. Food and Drug Administration (FDA) halted the marketing of 23andMe's personal genome test. The company was no longer allowed to provide health-related information on the basis of its genome scan. This week, the FDA authorized the marketing of 23andMe's Bloom Syndrome carrier test.
Has the FDA changed its opinion? Well, maybe not. The test that it approved this week is totally different from the one that it halted in 2013.
23andMe used to offer a broad array of genetic tests in a single genome service: carrier tests for hereditary diseases ranging from rare syndromes to cystic fibrosis and hereditary breast and ovarian cancer; predictive genetic tests for common diseases, and pharmacogenetic tests for drug response and adverse drug reactions. Of all these different DNA tests, the carrier test for Bloom Syndrome was among the ones that would most likely pass authorization by the FDA.
An extremely rare genetic disorder
Bloom syndrome is an autosomal recessive disorder, characterized by "short stature, sun-sensitive skin changes, an increased risk of cancer, and other health problems." Recessive means that both parents need to pass a genetic mutation for a child to develop the disorder. There is no treatment for Bloom syndrome, but surveillance of early cancer and other diseases may lead to better prognosis.
The disease is caused by genetic mutations only, and the genetic mutations are known in the vast majority of patients that have been diagnosed to date.
What FDA approval means and what it doesn't
FDA evaluates the safety and effectiveness of the test. It investigates whether harmful effects can be expected from testing and whether the test does what it says to do. FDA must have assessed, understandably, that the likelihood of harmful effects is low and that the test is accurately and reliably reporting carrier status for Bloom syndrome.
FDA approval does not mean that the Bloom syndrome carrier test is a useful test. It is not up to FDA to make recommendations about who should take the test and for what purposes, nor to advise against its use.
Because Bloom syndrome presents before or in childhood, genetic testing has little utility for most healthy adults. Genetic testing may only be useful for prospective parents, who might learn that they have a 25 percent probability that their child has Bloom syndrome if they both carry a mutation in the BLM gene. Yet, because the disease is extremely rare, the number of couples that both carry a genetic mutation is extremely rare too.
What is next?
23andMe has worked with the FDA towards approval of their service for several years. Starting with a least controversial genetic test after being halted in 2013 was, for both parties, a smart choice to test the waters and work towards further regulation from there. With the approval of the Bloom syndrome DNA test, there is now a starting point for scientific, regulatory and public discussion on the future of direct-to-consumer medical genetic testing.
In the coming months and years, FDA may likely approve carrier testing for other disorders like Bloom syndrome -- diseases that are rare, completely caused by known genetic mutations, present before or in childhood, and have opportunities for treatment or surveillance. Yet, approval of genetic tests for other diseases will first require a redefinition of the criteria of safety and effectiveness in the context of direct-to-consumer medical genetic testing. This redefinition should consider the evaluation of the potential harmful consequences from knowing one's genetic status and the assessment of effectiveness for predictive genetic tests with probabilistic results, among others.
In 2013, FDA halted the marketing because of concerns about the hereditary breast cancer and pharmacogenetic tests. That is where the real challenges around the safety and effectiveness of direct-to-consumer medical genetic testing are. It would have been a big shift if the FDA had changed that opinion, as there have been no major improvements in the scientific evidence for clinical validity and utility that asked for a reconsideration.
FDA's decision to approve 23andMe's Bloom syndrome carrier test is a first step for the online offer of medical genetic testing, but the real regulatory breakthroughs have yet to come.