How Genomic Testing Fits into Proactive Preventive Care

Sponsored by Neogen

Canine genetic testing has been commercially available for >20 years, but there have been significant changes since the annotation of the canine genome was completed in 2004. Over time, our knowledge of animal genomics has increased, and with that increased knowledge base, the benefits of genomic testing have expanded.

With an improved understanding of the canine genome, we have learned that genetic factors underlie many animal diseases, including cancer, diabetes, and epilepsy.¹ Since the dog genome was first sequenced, a great deal has been discovered regarding the genetics of disease susceptibility, underpinnings of physical traits, and even behavior.¹ Much of this research has been driven by studies that utilize noninvasive canine DNA samples to investigate the genetic underpinnings of >450 potential models for human disease.²

Being able to identify genetic markers of these diseases and others at an early age can offer several benefits. Information gained through genetic testing can help pet owners prepare for the future and make smart breeding decisions while also allowing veterinary teams to offer proactive disease prevention and screening options.

Is There Evidence to Support Genomic Testing?

Although a genetic basis has long been suspected for a number of conditions, the degree of evidence for these links is variable. Some conditions have a well-described genetic basis, whereas other conditions are still being studied. Although genomic testing can be helpful in pre-breeding screening and in identifying single-gene mutations such as the multidrug sensitivity gene (MDR1 gene, also known as ABCB1 gene), emerging research has shown a genomic link for more complex conditions that are more common and actionable in veterinary practice.

Intervertebral disk disease and obesity, for example, each have a clearly identified genetic basis. Researchers have identified that the overexpression of an FGF4 retrogene on chromosome 12 is responsible for canine intervertebral disk disease.^3-5 In Labrador retrievers, a deletion in the POMC gene has been determined to be associated with obesity⁶; in addition, further studies have identified epigenetic influences on POMC in humans that are also associated with obesity.⁷ Although these are just 2 of several examples already supported by research, further investigation is expected to provide additional evidence of genetic influences on animal diseases.

Incorporating Genomic Testing into General Practice

Genomic testing offers multiple benefits for pets, pet owners, and veterinary teams. Therefore, practices should consider the use of genomic testing as a routine diagnostic tool for patients. To successfully incorporate genomic testing into a busy practice, however, it is important to think through workflow considerations, as well as the importance of educating the team on the benefits of genomic testing.

Genomic testing should ideally be performed at an early age, even prior to spay or neuter surgery. Early testing can be used to guide breeding decisions, as well as to identify dogs at higher risk for anesthetic complications or bleeding disorders. Veterinary teams should consider making testing a routine component of the puppy visit sequence to ensure all owners are offered this valuable service.

To help integrate widespread genomic testing into practice, it is important to establish a communication plan regarding how the veterinary team can discuss testing and results with clients. Veterinarians may wish to offer all patients a broad-based screening test that can identify risk for common conditions and provide actionable results for clients and the veterinary team. Considerations may be different for purebred dogs or candidates for a breeding program, which may benefit from focused testing for markers with known relevance to a particular breed; they may also be offered a broad-based screening panel, keeping in mind the clinical relevance of the tests on the panel for that breed.

When results are received, a veterinarian should review them to interpret how they apply to the patient, and the veterinarian or veterinary technician will contact the client to discuss the results, potential risks identified on the panel, and any recommended next action steps. If a pet may be used for breeding, ongoing communications could include a conversation about clinical relevance of these results regarding heritability of any disease or risk factors identified. For patients at clinical risk for a condition, veterinary hospitals may want to have additional information to send home about what steps to take to prevent illness and signs to look for that would necessitate further treatment. For example, if pets are found to be highly likely to develop intervertebral disk disease, clients may want to consider keeping them at a healthy body weight, providing stairs or a ramp up to furniture to avoid jumping, and being aware of early signs of back pain. Ultimately, however, it is up to each practice to think through how they can most effectively and efficiently discuss genetic testing results with their clientele.

Conclusion

Genomic testing is a valuable source of information for veterinarians, pet owners, and the broader animal health community. As genomic testing becomes more commonplace and ubiquitous in practice, advances in this field will continue to occur. These advances will allow these tests to offer even greater benefits, such as contributing to the development of targeted therapies based on patient DNA and advanced cancer diagnostics.