If you find yourself working in small animal general practice after graduation, there’s a good chance that you will be asked to perform canine genetic testing. In some practices, such as Banfield® hospitals, genetic testing is viewed as an ordinary component of canine preventative care.
In other practices, genetic testing is an option that is available when clients specifically request it (which may happen rarely or frequently, depending on the practice).
Regardless of how your practice views genetic testing, it’s important to have at least some familiarity with key concepts and how to utilize this information.
1. Research the specific test your practice offers.
There is a lot of variation between commercially available genetic tests. Therefore, there are few one-size-fits-all comments that can be made about genetic testing and it’s important to research the specific test that is offered in your practice.
In general, most commercially available canine genetic tests strive to identify breeds and look for signs of the following conditions: multidrug resistance, von Willebrand’s disease, Factor VII deficiency, progressive retinal atrophy, exercise-induced collapse, and degenerative myelopathy. However, there is a long list of additional genetic tests that may also be incorporated into a genetic testing panel, depending on the test provider. Therefore, it’s important to research the specific test offered by your practice, in order to understand how it may benefit your patients.
2. Understand the difference between genetic markers and disease-causing genes.
In some cases, genetic testing can be used to directly identify a disease-causing gene. In many cases, however, genetic tests identify markers that are associated with a disease-causing gene, due to proximity on the chromosome. While genetic markers linked to a particular condition may suggest an increased likelihood of a dog developing that condition, these markers should not be viewed as definitive evidence that the pet will develop the condition.
It’s important to understand the distinction between genetic mutations and genetic markers. Knowing which abnormality you are dealing with determines your next steps upon receiving an abnormal result, as well as influencing the conversation that you will have with the dog’s owner. When you receive an abnormal result on a patient, take some time to look at what that result actually means.
3. Set realistic client expectations.
Veterinary genetic testing has come a long way since it was first introduced. However, there’s still a lot we don’t know. Many conditions are polygenic, which means that a single mutation cannot reliably predict the development of disease. Animals with a particular mutation associated with a polygenic disease may be at above-average risk of developing clinical disease, but there is still a very real possibility that they might remain clinically unaffected. Other mutations may only cause disease in the presence of certain environmental factors.
Clients need to understand that genetic testing isn’t a magic ball; it doesn’t allow us to see the future. It can provide information about how likely their pet is to develop a given condition, but in many cases further testing or a “wait and see” approach may still be necessary. Setting realistic client expectations before performing genetic testing can make post-testing conversations easier and less stressful for both you and your client.
4. Help clients understand which abnormal results are relevant and actionable.
Some genetic testing panels provide massive quantities of information, which can be overwhelming for clients. For this reason, many specialists recommend performing genetic tests for specific conditions of concern in a given patient, instead of taking a broad “shotgun” approach to genetic testing.
For example, when performing a large genetic panel, what do you do with the dog that comes back as a carrier for two or three separate conditions? In reality, this information is probably not very relevant unless the owner plans to breed the dog (with the exception of von Willebrand’s disease and some other clotting disorders), but it’s important to help clients sift through this information so they can determine what information is and isn’t actionable for their particular pet.
5. Pay attention to ongoing developments.
Genetic testing is developing at a rapid rate, with new advances expected on a regular basis. Try to stay current on these advances, so that you are equipped to advise clients who have questions on this topic. With time, the list of conditions that can be diagnosed through genetic testing will gradually increase; staying current will help you offer the best possible care to your clients.