Your patient just got some interesting news. He is 17 percent Eastern European, he probably sneezes in bright sunlight, and he has “the gene” for Alzheimer Disease.
That’s right, your patient just had genetic testing done by a company like 23andMe. The biotech firm lets its customers send in a saliva sample to have DNA analyzed for ancestry, common physical traits, and genetic disease risk.
This hasn’t always been the case. In 2013, the FDA ordered 23andMe to stop providing disease risk assessments for their customers. The agency was concerned that individuals didn’t have the necessary knowledge to appropriately interpret such risks. But in 2015, the FDA backed off and began allowing 23andMe to provide information about carrier status. And then in April of 2017, the FDA expanded the permission to include risks for ten genetic conditions, among them late-onset Alzheimer Disease.
This move was not without controversy. In the case of Alzheimer Disease, the patient is only tested for the ε4 genetic variant of APOE, which has a complex relationship with Alzheimer Disease. The association varies between races and is diminished in those over 80. One genetic copy of the variant increases the risk of Alzheimer Disease by two to three times. Two copies increase the risk twelve-fold. Of note, there is a baseline risk without the variant, and there are other known genetic causes of Alzheimer Disease that are not tested for by the service.
Most individuals who order these tests to find out about their great-grandparents’ homeland are not equipped to interpret such results. This creates a new role for physicians, particularly neurologists, who will likely field questions about the genetic tests for Alzheimer Disease and other neurological conditions as they are added to the testing panel.
As testing services like 23andMe grow more popular, neurologists will need to be able to help patients make sense of the findings. For example, how does the presence of one or two copies of the ε4 genetic variations affect risk? How do gender, ethnicity, and age play into risk? And, perhaps more to the point, what does it mean if the variant is absent? Do patients understand that the absence of the variant doesn’t mean the absence of risk?
Forbes reported that 23andMe had two million customers as of April 2017, which represents a 250 percent increase in just two years. Ten to 15 percent of the population carries the ε4 variant. This translates into 300,000 who know they have the variant from this single test, and that number is rapidly increasing. While neurologists may not have encountered these folks yet, they are out there and the number is growing. It’s only a matter of time until they land in your office.
Whether or not you think the FDA was right in granting their approval, the deed is done. This means neurologists must understand what information companies like 23andMe give to its customers and how to appropriately counsel patients on its meaning. This is certain to become an important task neurologists will find themselves adding to their practice. Thinking ahead will keep it from becoming just another unreimbursed administrative task. Putting a plan into place now will allow you to integrate it in such a way that consumer genetic testing services help you grow your practice and provide better medical care for your patients.