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Whether a practice decides to embrace the concept of genetic testing depends on its strategy for delivering healthcare. There is no doubt that more validation is needed in both human and pet genetic health screening, but that doesn't negate the real value in providing such a proactive resource for pet owners.

When it comes to matching DNA from an individual with the likelihood of disease development in the future, it very much depends on the specificity of the genetic variant being measured, and the individual being tested. That's why it takes a veterinary team to help interpret DNA test results, counsel pet owners accordingly (see 3.8 Genetic counseling), and develop a relevant personalized care plan.

Part of the reason that disease detection is not simple is that diseases and traits can be influenced by a variety of different genes, as well as environmental factors. Atopic dermatitis (environmental allergy), for example, is a skin condition that tends to run in families and there are definite breed predispositions, but that doesn't mean that any one DNA test developed will be able to predict onset with any certainty in all pets and all breeds. The body has a lot of redundant systems in place, so even if there is a genetic issue somewhere, it may be possible for the body to compensate through mechanisms elsewhere. Another important point to consider is that genes themselves don't cause diseases. Genes provide the blueprint for creating proteins, and it is typically defective and poorly functional proteins that lead to the clinical picture that we interpret as disease … often with significant environmental influences.

At this point in time, there are a few hundred genetic variants known to affect the health of pets, but new associations are being uncovered on a regular basis. The important thing to remember with such testing is that the most predictive tests will be for medical conditions controlled by a single gene pair (such as vWD type I in the Doberman pinscher, progressive retinal atrophy‐rcd1 in the Irish setter, or ichthyosis‐A in the golden retriever). The vast majority of diseases seen in pets (such as atopic dermatitis, heart disease, diabetes mellitus, obesity, periodontal disease, seizure disorders, etc.) actually have a more complicated pattern of inheritance, and may involve multiple genes as well as environmental influencers, and genetic tests developed for these types of conditions should be expected to be less predictive, even if they still contribute useful information [4]. Even for conditions such as hip dysplasia, heritability is important, but environmental influences often have more impact on clinical expression of the disorder than does genetics (heritability ~0.25). Genetic variants may also have some association with disease in one breed but not necessarily in others and this is not a fault of the testing, but just a reality of pet‐specific care and breed‐specific risk.

Because of the complexity of biological systems, just because there is a genetic mutation that leads to a poorly functional protein doesn't mean that the animal will definitely develop disease. We often describe this as penetrance, the likelihood that a given mutation in an animal will result in clinical disease. Not surprisingly, we don't have enough of this information for many genetic tests, nor for those tests in different breeds. Yet another form of variation is known as expressivity. This refers to the variability in clinical presentation that can be seen in individuals, with some animals with the same genotype being more severely affected, and others less so.

Part of the complexity of such testing is also a great opportunity for veterinary teams. If genetic testing didn't require any expertise or interpretation, there would be little reason for pet owners to want to work with veterinary teams to keep their pets healthy. It is this ability to counsel and coach that makes the veterinary team critical to the success of such programs, and to the evidence‐based creation of personalized care plans.