Don’t use dog DNA tests to make life-or-death decisions for your pet, experts warn
But three canine genetics experts have now hurled cold water on those claims, saying the entire business of consumer-marketed canine genetics testing is an “untamed wilderness” of weak science, unvalidated outcomes and conflicts of interest.
Their opinion piece, published last week in the journal Nature, says some dog owners are making decisions about euthanasia and serious veterinary treatments based on DNA tests that come with minimal warnings, vague details about tests and no government oversight. The paper calls for standards and guidelines that, the authors say, may need to become law to resolve the problems – especially as the field, with hundreds of thousands of dogs already being tested each year, continues to grow.
“We don’t understand why nobody is talking about it,” said co-author Lisa Moses, a veterinarian and research scholar at Harvard Medical School. “We’re really worried that there’s this large-scale misinformation about what the tests’ power really is and how they’re being used for life-and death questions.”
The commentary sparked debate within the veterinary world. Several industry experts said they agreed with its general premise that there’s a problem with the way dog DNA tests are marketed, but they defended what they called decades’ worth of science that has led to today’s tests – when that science is used, in their view, properly.
Diane Brown, CEO of the AKC Canine Health Foundation, an independent affiliate of the American Kennel Club, said her group has contributed about $20 million since 1995 to research about specific gene mutations that cause disease in certain breeds of dogs. But what’s happening now, with the kinds of catchall DNA tests available to all dog owners, is an entirely different proposition, she said.
“When these new marketing companies come in, they pull this information down, they throw it into these multiplex tests, and we’re talking about apples and oranges,” Brown says. “The premise that I took from that Nature commentary is that there is an unregulated marketing-to-consumer testing available that is incredibly misleading, and I completely agree. These multiplex, go spend $65 to have a list of diseases given back to you, is virtually meaningless.”
Dog owners who purchase such tests swab their pets’ cheek and mail the sample to the testing company. Within a few weeks, they receive a report that can detail the animal’s breed ancestry as well as its genetic disease risk assessment. The two leading dog DNA tests for consumers are the Mars-owned Wisdom Panel, which a company official said has been used to test more than a million dogs, and Embark.
One problem with mass-market dog DNA tests, some experts say, is that they often identify gene mutations that have been linked to disease only in certain breeds. For instance, if research has shown that a mutation is associated with cancer in golden retrievers, that doesn’t necessarily mean the same mutation will cause cancer in a Boston terrier – but the mutation still shows up on the terrier’s report. So its owner might then rush to a veterinarian, who, given the recent nature of the science, may not have a solid understanding of what the report really means.
Elinor Karlsson, a co-author of the Nature paper and director of vertebrate genomics at the Broad Institute of Harvard and the Massachusetts Institute of Technology, said the core problem is how consumer test results are being interpreted. Simply having a genetic mutation, she says, doesn’t mean disease will follow or that veterinary intervention is required.
“Finding something and then using it clinically are two different things,” Karlsson said. “If you take 1,000 dogs and look at them, the ones that carry that mutation, what are the chances that they’re going to get sick? What does the information mean about whether your dog is going to get the disease? That’s the piece we’re missing right now.”
What is possible, experts say, is to identify some genetic mutations in certain breeds and make sure those dogs are not bred with others with the same mutations, thus reducing the chance of inherited disease in puppies. For dog breeders, they say, that type of genetic testing is key.
But for consumers looking at reports about mutations in, say, a mutt, making sense of results is a murkier affair – a science unto itself that’s only now beginning to be taught in veterinary schools, which have begun to train canine genetics counselors.
“Some of these companies are doing that counseling, but others just want to sell these tests,” said Jerold Bell, a board member of the Orthopedic Foundation for Animals. “It’s an industry that’s in its infancy, and the commercialization has preceded the educational process.”
Kari Ekenstedt, an assistant professor of anatomy and genetics at Purdue University‘s College of Veterinary Medicine, explained it this way: “If your dog had an eye condition that a general vet wasn’t comfortable dealing with, they would refer to a [board-certified] veterinary ophthalmologist. We desperately need something like this for veterinary genetics. Until that happens, veterinary genetics experts will be much harder to find, and thus bad advice and inappropriate testing will run rampant.”
Angela Hughes, veterinary genetics research manager with the Mars Wisdom Panel, said she agrees that finding a genetic mutation is different from knowing what, if anything, to do about it – and that her company makes that distinction clear for consumers.
“This panel has a lot of benefits, but it has to be used with caution,” Hughes says. “We may know of a mutation in Dobermans, and then we see it in Dachshunds, then we have to do clinical validation studies to follow up and investigate that. What does the mutation actually do in Dachshunds? So, we flag it for the Dachshund owners and very clearly state what is a known problem in a breed and what is a potential concern that we are investigating with additional studies.”
Embark officials, too, said that company does proactive genetics counseling for customers and also offers it to breeders and veterinarians.
“As you get more genetic information, there are more opportunities to misinterpret it,” said Adam Boyko, a canine geneticist at Cornell University who is Embark’s chief science officer. “Dog breeders, when they started testing and there were one and two mutations, that wasn’t so bad. But when you’re testing for 50 or 60 mutations, you have to understand that it’s not always deleterious.”
Even so, he said, DNA tests like Embark’s can assist consumers in making veterinary decisions.
“It’s going to exclude certain diagnoses – never 100 percent, there can always be a new mutation that causes a disease – but it can definitely reduce the need for extra veterinary tests,” he says.
Moses, the co-author of the Nature paper, said consumers should think of the tests as interesting and fun, but not use them to make veterinary decisions.
“Put pressure on the companies that are in veterinary medicine regulatory bodies,” she says. “As consumers, you’re not getting much for your money here.”