Blog Archives for the year 2019

The Veterinarian's Corner: Incorrectly Recorded Canine Parentage and the Effect on Genetic Health

The Veterinarian's Corner: Incorrectly Recorded Canine Parentage and the Effect on Genetic Health

Over the past two decades, usage of genetic testing technologies has revolutionized the world of dog breeding. Once limited to selective breeding practices based upon the characteristics or disease states that could be physically observed in a dog, genetic testing has allowed dog breeders to uncover the inherited genetic variants (mutations) that are not being expressed in an individual but may be expressed in their offspring. By comparing the disease-associated mutations inherited by a dog to those of a prospective mate, informed breeding decisions can be made to avoid producing puppies with these diseases. However, despite the immense value of genetic disease testing in the production of healthy puppies, incorrect assumptions about the parentage of a litter can have disastrous consequences for the health of a kennel, even when parental genetic disease testing results are 100% accurate.

Clear by Parentage/Hereditary Clear

In ideal situations, potential dams and sires are tested for breed-specific, disease-associated genetic mutations prior to being bred. If both parents are found to be free of these mutations (often referred to as being “clear”), it can be assumed for practical purposes that the offspring are also clear of the same mutations. With this understanding, it is common ...

Knowledge is Power in Dog Breeding

Knowledge is Power in Dog Breeding

I was recently contacted by a friend who is looking to buy a new puppy and wanted to make sure that the parents had been tested, and if not, that the prospective puppy had been tested for all of the genetic disease that are found in that breed.  When she asked the breeder if testing had been done, the answer was “no”. When she asked if she could have a sample sent to Paw Print Genetics prior to buying the puppy, the breeder promptly returned her deposit and said that the puppy was no longer available. Although feeling devastated, my friend knew that she was asking the right questions. After all, she is looking for a new family member!

Was the breeder hiding something or just simply afraid of what she might find if she were to do genetic testing?  We won’t know the answer, but I think a lot of what keeps some breeders from testing is fear of the unknown.  What if they find something in their lines?  Will they be stuck with dogs that they can’t sell?  Will others think that they have “bad” dogs?  Actually, doing genetic testing will increase ...

The Veterinarian’s Corner: Variable Disease Presentation and How Genetic Testing Can Help

The Veterinarian’s Corner: Variable Disease Presentation and How Genetic Testing Can Help

Every veterinarian leaves veterinary school with a mental laundry list of animal diseases and their textbook presentations. While this knowledge serves the young graduate well in most circumstances, with clinical experience and mentorship comes the ability for veterinarians to expand their mental notes about the various ways some diseases can present in the real world. For some inherited canine diseases, genetic testing has allowed the practitioner to correlate a broader set of clinical signs for dogs affected by identical underlying genetic mutations. This variability in disease phenotype, known as variable expressivity, is a result of the combined effect of all genetic and environmental factors influencing each individual and can add significant challenge to some diagnoses. However, supplementing a disease workup with genetic test results can prove invaluable in diagnosing inherited diseases that have the frustrating attribute of rarely presenting the same way twice.

Collie Eye Anomaly

Now known to occur in well over a dozen breeds, the recessively inherited collie eye anomaly or CEA (also known as choroidal hypoplasia) is a relatively common eye disease of dogs and a good example of a disorder which can have diagnostic challenges due to its phenotypic variability. CEA is caused by a deletion ...

Fireworks and Fido: How to Make It Through the July 4th Holiday

Fireworks and Fido: How to Make It Through the July 4th Holiday

With the Fourth of July just around the corner, you need to be mindful of how your dog reacts to fireworks and loud noises and take this into consideration when planning Independence Day activities.

For some dogs, fireworks are a non-issue. Hunting dogs and others that are used to loud noises, the thunderous booms that accompany the flash and sparkle of pyrotechnics, can be just another night.

However, for others, the stress experienced by dogs during fireworks often triggers the fight-or-flight response. The loud noises usually make the dog want to leave the situation – animal-control services see a 30-percent increase in lost pets during the time aournd the 4th of July holiday. Although you need to take the appropriate steps to keep your pet safe and secure, so that you don't risk losing your pet as many may run away, the stress also increases the possibility of behavior issues, such a biting, even in a dog that has never shown aggression. 

To keep your dog protected, make sure you provide a safe place for it during the holiday season – their crate is an excellent spot that is very secure both physically and psychologically. Always leash your dog before going ...

The Veterinarian’s Corner: Genetic Heterogeneity and Its Importance in Dog Breeding

The Veterinarian’s Corner: Genetic Heterogeneity and Its Importance in Dog Breeding

The discovery of various disease-associated genetic mutations has greatly changed the way some inherited canine diseases are categorized and perceived by the veterinary community. Through the use of genetic testing developed to identify these discovered mutations, various diseases which were once assumed to have a single underlying molecular cause (due to similarity between disease states) have been found in some cases to actually be caused by many different mutations, often in different genes. This phenomenon, known as genetic heterogeneity, elucidates the way genes work together in pathways and how a disruption in different genes of a pathway may result in similar or nearly identical disease states despite seemingly disparate underlying molecular etiologies. Understanding that there may be one of many different genetic mutations responsible for a dog’s clinical signs can help plot a better course for veterinarians to obtain an accurate, definitive diagnosis and in some cases, may alter treatment strategies.

Pet Owner vs Breeder

The accuracy and specificity of an inherited disease diagnosis are particularly important in the world of dog breeding where every potential health issue must be considered prior to breeding. Unlike general pet owners who may not need to know the specific underlying molecular mechanisms of ...

The Complexities of Genetic Testing and Counseling: Accuracy, Penetrance and Validity, Oh My!

The Complexities of Genetic Testing and Counseling: Accuracy, Penetrance and Validity, Oh My!
Photo showing the diversity of coat colors and patterns within the Australian Shepherd.

As a laboratory that works directly with breeders and dog owners, Paw Print Genetics (PPG) is often asked to reassure the customer that our tests accurately determine whether a dog will get a disease.  The customer is actually asking a couple of different questions; one involving the accuracy of the test itself and one regarding the clinical validity of the test. It is important to understand the questions being asked so that the answers make sense.

The first question being asked is: Does the test perform accurately to determine if a dog is normal/clear, a carrier of one copy of the mutation or at risk, having two copies of the mutation. At PPG, our tests are extensively validated and must show 99.9% specificity and sensitivity before being available for ordering. Sensitivity is defined as the proportion of samples with a known mutation that are correctly classified/identified as carrier or at risk by their genotypes. Specificity is defined as the proportion of samples with no known mutation that are correctly classified/identified with the wildtype (normal) genotype for the disease.  This all refers to whether the test result accurately reflects the true genotype of the individual. At ...