Dog DNA test-maker seeks to identify deadly heart defect in Labrador retrievers

2019-8-6 iStock-912738474 Embark heart study - blog.jpg

Embark Veterinary, makers of the Embark Dog DNA test and a research partner of the Cornell University College of Veterinary Medicine, is launching a new study on canine Tricuspid Valve Dysplasia (TVD) with the goal of developing DNA-based test for the disorder.

TVD is an often-fatal congenital heart defect that affects up to 7% of all dogs and is found most commonly in purebred Labrador retrievers, who account for 25% of cases. To accelerate its research, Embark has issued a worldwide call for DNA samples from Labs with TVD.

NEWStat reached out to Adam Boyko, MS, PhD, founder and Chief Science Officer of Embark Veterinary, and an associate professor in the Department of Biomedical Sciences at the Cornell University College of Veterinary Medicine, to find out more.

NEWStat: Why did Embark turn their focus on TVD in Labrador retrievers? With so many possible genetic conditions to research in so many breeds, why this one in particular?

Adam Boyko: We picked TVD because it can really negatively affect quality of life, but is present early in life, and is often detected on routine cardiology screens such as the OFA (Orthopedic Foundation for Animals) cardiac exam. There is evidence [see below] that TVD is highly heritable, so this is a good disease to go after with our current sample size. As we approach a million dogs [in the Embark database], even more common and complex conditions [such as] hip dysplasia, allergies, and cancer will become more tractable for us to study.

NEWStat: How long will the study take?

AB: We expect this study to take place over two years—good science takes time! That being said, the timeline for this project is shorter with Embark than if we were starting this initiative without a direct-to-consumer platform. As part of this study, the consumer is essentially paying their research forward: They get breed, ancestry, traits, and known health risk variants, and they get to contribute to research about unknown health risk variants—in this case, TVD risk.

NEWStat: If you discover a genetic basis for TVD, what’s the next step in treating it?

AB: The primary objective would be to help breeders make breeding decisions that reduced the incidence of TVD in the Lab population. However, there are also a portion of dogs who go undiagnosed until they present to the veterinarian in really bad shape (congestive heart failure). By testing puppies, we’d hopefully be able to help veterinarians become proactive about diagnosing, managing, and/or treating this condition.

NEWStat: Why do researchers believe that there’s genetic basis for TVD?

AB: The fact that Labradors are overrepresented in the case population for TVD suggests that there is some genetic contribution to the disease. In addition, quite a bit of work has already gone into understanding the genetics of this trait. Famula et al., 2002 did work that suggests that TVD is heritable in Labs [and] Andelfinger et al., 2002 actually implicated a region of the genome as being involved.

NEWStat: How many conditions have researchers at Embark found a genetic basis for in dogs to date? What are some examples?

AB: We published the first novel genetic discovery in a nonhuman species, the genetic basis of blue eyes in Arctic Circle breeds, just last year (Deane-Coe et al., 2018). We have also published two papers that explore genetic measures of inbreeding (Sams et al., 2018) and the consequences of inbreeding on reproduction (Chu et al., 2019). Now that we’ve tested hundreds of thousands of dogs, we have the statistical power to start going after more complex traits, such as disease risk for disorders like TVD.

Labrador owners with dogs diagnosed with TVD by a board-certified veterinary cardiologist (including those that perform routine OFA heart screenings) are encouraged to participate in the study. Participation is free, and all data collected and assessed from participants will be anonymized to ensure privacy. Participants will be provided with a comprehensive Embark DNA profile in return for participating in the study. Learn more and sign up to participate.

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