At-Home DNA Tests: Crystal Ball With a Caveat
Veterinarians should open the conversation with clients about at-home DNA tests to make sure they interpret the results appropriately.
Veterinary medicine has historically been largely reactionary, says Ernie Ward, DVM, CVFT. But the tide might be turning.
“Now we’re in an era where we have a physiological crystal ball,” he says. “When you know you or your pet has a greater risk of developing, say, diabetes, you may be able to avoid being diagnosed with the disease with diet and exercise. Genetic tests are one more way to get a glimpse of the future.”
Pros and Cons
The change has come about with the popularity of direct-to-consumer DNA tests for pets, which use a simple cheek swab collected by the animal owner. Not surprisingly, these tests follow in the steps of such tests for humans.
Leslie A. Lyons, PhD, makes a point to note that despite the benefits of the tests, there are potential pitfalls.
“Just like for any species—humans or cats or dogs—one of the main fears is that people will read the results and not interpret them properly,” says Dr. Lyons, the Gilbreath-McLorn Endowed Professor of Comparative Medicine at the University of Missouri College of Veterinary Medicine. “The company might not provide sufficient genetic counseling for their genetic tests. This can be common for human medicine as well.”
The biggest potential hurdle for clients is understanding that their pet’s genetic predisposition for a disease does not equate to the diagnosis of that disease.
“That’s not true at all,” says Dr. Ward, who is an adviser for Basepaws, a manufacturer of cat DNA tests. “We are entering an era where we’re trying to prevent poor outcomes. Genetic tests are one more way to get a glimpse of the future.”
There are other widely held misconceptions, Dr. Ward says.
“One is that your genes are your destiny. After 40 to 50 years of research, we’ve discovered that genes are about 30% of total health. Sometimes we can’t change outcomes, but other times we can. We are more in control of health and outcomes today than we know.
“There is power is knowing the path genes carve out for you,” he says. “Historically, we have looked at parents’, grandparents’, great-grandparents’ health. In my family, the males died too early from heart disease. In my 20s, I started thinking about how I could avoid that, and decided to become vegan. Knowing a pet has a greater risk to develop heart disease, we can see where the genetic risks lie and take action. The most impactful actions are diet, exercise, and maintaining lean body mass. These genetic tests nudge pet parents toward healthier habits.”
Dr. Lyons says the veterinarian has a difficult role in direct-to-consumer DNA testing.
“Historically, genetics hasn’t been emphasized in veterinary training,” she says. “It takes a dedicated effort to understand the meaning of each genetic test and what it means for someone’s cat or dog. Right now, the veterinarian would have to try to explain the tests as well as the services.”
In human medicine, she notes, the genetic counselor takes on that role, or perhaps a patient is sent to a specialist. “The veterinarian has to wear many hats,” she says. Despite this challenge, Dr. Lyons sees a legitimate place in veterinary medicine for the tests.
“They are good if a breeder wants to know if an animal carries or is at risk for a specific genetic condition,” she says. “In that case, the breeder can change plans for the animal. If a cat is at risk for polycystic kidney disease, the veterinarian will probably want to monitor the cat for the rest of its life for developing cysts or renal failure and perform ultrasounds every few years. The whole goal of genetic testing is to prevent the animal from harm, changing breeding so as not to produce at-risk animals.”
The Veterinarian’s Role
Veterinarians tend to be a generally conservative group, says Aaron Massecar, PhD, vice president of VEGucation for the Veterinary Emergency Group.
“They typically are not early adopters,” Dr. Massecar says. “Some are, but as a whole they are hesitant. They want more time to see proof of the scientific validity of tests and services. These veterinarians can frame DNA tests as another way for an owner to understand their animal and increase the human-animal bond.
“A DNA test is an opportunity for the veterinarian to say ‘let’s get you more information on your animal and maybe what we should be looking for.’ If tests show a predisposition for hip dysplasia, maybe we can use [a therapeutic diet] for the pet’s food.”
What should veterinarians look for in the realm of pet DNA tests?
“They should be aware of what companies are out there, what tests they perform—some do breed identification/ancestry, some phenotypes, others full health information—and start to build a rapport,” Dr. Lyons says. “There aren’t dozens of companies yet, only a handful. Know the differences between how they do tests. It’s primarily customer service. If you call the company and say ‘I need help interpreting tests,’ if they don’t fall head over heels to help you, go someplace else.”
She recommends using a testing laboratory that is associated with a research university. “It will be more interested in making sure tests are correct and providing good customer service than a company removed from a university. Universities are the ones developing the tests,” Dr. Lyons says.
Dr. Massecar also recommends that veterinarians develop a good understanding of the tests available in order to guide clients. BOX 1 lists some of the products available for consumers.
“Learn about the research behind them, and provide the client as much information as possible. Then in terms of counseling an interested client, the veterinarian can say, ‘I’ve looked into these tests and can recommend this one.’”
This allows the veterinarian to open a conversation with the client, he says.
“The veterinarian can ask the client if there’s particular information they’re looking for, and ask if there’s anything they can do in the meantime to help the client better understand their animal. Perhaps do some diagnostics to see if more is going on than predisposition,” Dr. Massecar says. “This can lead to developing a deeper, more meaningful relationship with the pet owner.”
He sees use of DNA tests continuing to grow as costs come down. “The trend is toward more preventive maintenance,” Dr. Massecar says. “Some clients are just curious about their animal; they’re not necessarily interested in health predispositions. A lot of people just want a little more understanding about their pet. Framing it that way is most productive for the veterinarian.
“These tests are not about pet owners trying to circumvent veterinarians. It’s a means by which people can have a deeper relationship with their animal. It’s an expression of care, and gives veterinarians an opportunity to be open to the discussion and incorporate testing into their practice.”