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With pet‐specific care, the goal is to be proactive and address potential issues at the earliest possible opportunity, preferably when problems are still subclinical. DNA testing can be very useful for this purpose, as it can be run very early in life, even as early as 1 day of age (see 3.4 Predicting and Eliminating Disease Traits).

Genetic testing is a useful tool as long as veterinary teams have realistic expectations. The purpose of genetic tests is not necessarily to confirm a diagnosis, but to understand risk factors that could be relevant for an individual pet, even issues that may develop much later in life [4]. So, it is extremely important that veterinary team members understand the difference between association and causation when it comes to such testing.

The vast majority of DNA tests are not absolutely predictive because any one variant detected may not actually be causing the disease in its entirety (see 11.3 Heritable Health Conditions – By Disease). Most often, they just indicate suspected “risk” based on the statistical association of a variant to clinical disease, and it is up to the veterinary team to put such risks in perspective. For example, the skin condition dermatomyositis is often described as being autosomal dominant with variable expressivity (more on this term later), and confirmation of the diagnosis in affected individuals (usually collies, Shetland sheepdogs and their crosses) is based on biopsy. There are at least three different genetic variants “associated” with dermatomyositis risk, and when considered in aggregate, pets can often be classified as high risk, moderate risk, and low risk for developing dermatomyositis. This can be extremely useful for counseling owners of at‐risk pets, even if the predictive ability is not absolute. For some conditions in which there is genetic risk, there can also be future testing indicated. For example, a pet that has a relevant glaucoma variant detectable on genetic testing (in a breed at risk for this variant) doesn't mean that the pet will necessarily develop glaucoma, but it does suggest that further glaucoma screening by periodically evaluating intraocular pressure (IOP) is warranted for consideration. Based on the breed, a personalized care plan can incorporate such testing at appropriate intervals.

In most instances, it is practical to perform genetic screening at about 12 weeks of age. At that time, the pet should be well into vaccination and parasite control protocols, and hopefully enrolled in pet health insurance. Once again, the goal is not to try to diagnose disease in a healthy puppy or kitten with such screening, but to help prepare a risk profile for the animal so that pet‐specific recommendations can be made regarding prevention and early detection programs. For example, knowing a pet's multidrug resistant (mdr1) genetic status can help inform whether certain medications might be problematic if administered. Knowing the genotypic status for vWD can prove very useful if surgical intervention is being considered (including neutering). If veterinary teams consider that the point of genetic testing is to better appreciate potential risk, they will be able to relay more appropriate information to pet owners, and determine what future screening should be taking place in the personalized care plan.