Researchers have gained more insight into the genetic risk factors for asthma with hay fever thanks to consumer genetic testing. 23andMe, a direct-to-consumer gene testing company has conducted the first genome-wide association study of the combined conditions.
The research, published in the Journal of Allergy and Clinical Immunology was led by scientists at the QIMR Berghofer Medical Research Institute in Australia. Researchers pinpointed 11 independent genetic markers associated with asthma with hay fever. Two of them were at a level that significantly linked them to allergic disease.
David Hinds, Ph.D., study author and 23andMe principal scientist, said that while there had been evidence of a genetic link for the combined phenotype—asthma with hay fever—there hadn’t yet been a genome-wide study to further explore this connection before now.
“In this first-of-its-kind study, we've identified new genetic associations that can provide the means to identify people at risk for allergic disease with greater efficiency,” Hinds said.
According to previous studies, both conditions share 50 to 90 percent of their genetic susceptibility and 20 to 50 percent of their environmental susceptibility. 23andMe used data volunteered by 15,072 of its customers to make the finding. It also incorporated data from nearly 7,000 people involved in three other studies conducted in the U.K. and Australia.
23andMe Responds to FDA Warning Letter
This isn’t the first time 23andMe has been in the spotlight, but in the past it’s been due to the ongoing controversy over consumer genetic testing. Last year, the Food and Drug Administration (FDA) requested that the company stop marketing its genetic tests for health purposes.
Their marketing claimed that people could use 23andMe results to gauge their genetic risk for diseases—or to predict their reaction to prescription drugs.
The FDA has not approved any direct-to-consumer (DTC) genetic tests. 23andMe has a notification on its website that says it is not providing health-related genetic reports to customers at the moment—only ancestry information.
A 23andme spokesperson said that the company has discontinued new consumer access to health-related genetic tests while it completes the submission process for FDA approval. According to 23andMe, the FDA mandate does not apply to their allergy and other genome-wide association research.
“The 23andMe research model has remained unchanged, and 23andMe continues their educational and research efforts using their database of genetic and phenotypic data,” the representative said.
She added that participation in the research arm of the company is voluntary.
“Customers may choose to opt-in upon registration if they wish to participate,” she said.
Are DTC Genetic Tests Accurate?
Jeff Murray, M.D., a geneticist at the University of Iowa and former president of the American Society of Human Genetics (ASHG), said the testing done by DTC companies like 23andMe is focused on identifying genetic variants that may indicate a small risk for common diseases like type 2 diabetes and asthma.
They also do ancestry testing and testing for carriers of diseases like cystic fibrosis, but their tests for these single gene conditions are incomplete, and a negative result would not exclude someone from still being a carrier, Murray said.
“The common trait testing [like 23andMe does] also does not include many other environmental and familial factors that also affect risk, so they are best interpreted in the context of a professional in genetics who can explain the nuances and explore what the person’s needs and interests are,” Murray said, adding that the data they generate is scientifically accurate.
How Should Consumers Interpret Their Results?
Rene Almeling, Ph.D., an assistant professor at Yale University, agrees that a professional should interpret genetic test results, instead of consumers.
She said that about 65 percent of Americans believe that clinicians should be involved in explaining genetic test results. She reported the data in a survey published in Genetics in Medicine, along with Shana Kushner Gadarian, Ph.D., an assistant professor at the Maxwell School of Citizenship and Public Affairs at Syracuse University.
Katherine Wasson, Ph.D., an assistant professor at Loyola University’s Neiswanger Institute for Bioethics, said that many professional organizations recommend having a professional review genetic results due to the complex nature of genetic testing.
“How individual consumers understand and interpret this information without the help of a trained health professional is unclear, particularly as the science is changing rapidly,” she said.
She said her university conducted a qualitative study of 20 primary care patients who took a 23andMe genetic test. While most indicated they would or might talk to their physician about the results, less than half actually did.
“Some of the patients found the test and results interesting, but did not learn anything new. If consumers of DTC genetic testing receive results that they found worrying or required swift action, their response to this type of testing may be very different,” she said.
Note: This article was revised for clarity on 2/5/2014.