Category archives: The Veterinarian's Corner

Tissue Management Prior to Genetic Testing

Tissue Management Prior to Genetic Testing

Nothing brightens the schedule like seeing an 11:20am slot given to Mrs. Doe who is bringing in a three-day old litter for assessment, tails and dewclaws.  The whole clinic reminds you all morning that puppies are coming in.  Then the magic hour arrives and in comes Mrs. Doe with a laundry basket covered in a towel that is making a surprising level of grunts and squeals.  Wow! Thirteen little fuzzballs in varied states of activity from litter-surfing to dreamless slumber that makes you a little jealous.  You go through the exam; each one is fully formed with no gross congenital defects.  While prepping your tools for dewclaw removal and tail docking, Mrs. Doe asks that you save the remnants so she can have the litter tested with Paw Print Genetics for known disease-causing mutations in this breed.  Hmmm, what does this entail?

Typically, we recommend to clients who choose to submit cheek swabs to wait until they begin weening the pups off mom. This allows them to separate the puppies from their mother to reduce possible contamination by the mother’s milk that may remain in the puppies’ mouths.  Given that testing takes ...

Feline Genetic Health Screening with the CatScan- Benefits for Veterinary Practice

Feline Genetic Health Screening with the CatScan- Benefits for Veterinary Practice

The popularity of genetic health testing in domestic animals is rapidly increasing for a variety of different applications. Although genetic testing of dogs has been more widely recognized by the public than similar testing in cats, advancements in genetic testing are also becoming increasingly popular among those that have a special feline in their life. In order to address the genetic health concerns of our cat-loving friends and their wonderful felines, the team at Paw Print Genetics has developed the CatScan, a powerful genetic screening tool for inherited diseases and traits. Aside from its important use by feline breeders to make informed breeding decisions and to prevent the production of kittens with certain inherited diseases, the CatScan also has powerful applications in clinical veterinary medicine especially in cases where testing is performed early in a cat’s life or when the cat’s pedigree is unknown.  

Early Screening for Greatest Impact

From a technical perspective, the CatScan can be performed using cheek swabs from kittens of any age as long as it is possible to prevent contamination of their DNA sample with DNA from other cats or mother’s milk. However, testing kittens early (around the beginning of weaning) is a common ...

Paw Print Genetics Adds New Canine Genetic Disease Tests to Ever-Expanding Offerings

Paw Print Genetics Adds New Canine Genetic Disease Tests to Ever-Expanding Offerings

With the current, rapid pace of new genetic discoveries, inherited disease testing is quickly becoming a common part of clinical veterinary diagnostics. Paw Print Genetics is excited to announce the release of six new canine genetic disease tests, including highly anticipated tests for three diseases in retriever breeds; macular corneal dystrophy and congenital myasthenic syndrome in the Labrador retriever and neuronal ceroid lipofuscinosis 5 in the golden retriever.

Macular Corneal Dystrophy

With an estimated mutation carrier rate of 3.3% in a 2015 study of the UK Labrador retrievers, macular corneal dystrophy (MCD) is an inherited eye disease that that is likely to be encountered at some point in a small animal veterinarian’s career1.

Inherited in a recessive manner, Labradors with two copies of the associated CHST6 gene mutation typically present in middle age with MCD-associated vision loss. Affected dogs display decreased activity of an enzyme known as corneal glucosamine N-acetyl-6-sulfotransferase (C-GlcNAc6ST), which results in decreased sulfation of the corneal glycosaminoglycan, keratin sulfate (KS). Decreased sulfation of KS reduces its solubility, thus preventing its full metabolism and allowing for deposition into the extracellular space of the corneal stroma and Desmet’s membrane, and intracellularly in keratinocytes and corneal epithelial cells ...

For The Veterinarian: The Genetics of Shortened Limbs and the Association with Canine Intervertebral Disc Disease (IVDD)

For The Veterinarian: The Genetics of Shortened Limbs and the Association with Canine Intervertebral Disc Disease (IVDD)

Shortened legs are a major defining feature for some of today’s most popular domestic dog breeds. Although dogs with extreme shortening of the limbs likely come to mind when pondering this trait (such as dachshunds or basset hounds), many other breeds also display a more subtle or moderate limb shortening (e.g. West Highland white terrier, Nova Scotia duck tolling retriever, beagle). Unfortunately, in some breeds, dogs with shortened legs have also been found to be at an increased risk for early-onset intervertebral disc disease (IVDD). However, over the past several years, genetic discoveries and development of genetic testing have made it possible to better understand the short-legged appearance of some dog breeds and the genetic underpinnings which make some of these dogs more likely to develop IVDD.

Shortened Legs and Genetic Link to Intervertebral Disc Disease

Two genetic mutations associated with shorter limb length have been reported in domestic dogs2,4,5. Both mutations consist of a duplicated section of the canine FGF4 gene (called an FGF4-retrogene) which has been inserted into two aberrant locations of the genome; one copy has been inserted into a region on chromosome 12 (CFA12 FGF4 insertion) and the other copy has ...

Genetic Health Screening, the Canine HealthCheck, and Benefits for Veterinary Practice

Genetic Health Screening, the Canine HealthCheck, and Benefits for Veterinary Practice

The impact of canine genetic testing on veterinary medicine continues to grow as dog owners become increasingly interested in the genetic factors underlying their dogs’ health and how knowledge of these factors may improve the lives of their furry companions. Genetic screening tools which test for large numbers of deleterious genetic mutations, such as the Canine HealthCheck (CHC) developed by Paw Print Genetics (PPG), are particularly useful when performed on a young dog to identify specific inherited health concerns; especially in cases where the lineage of the dog is unknown.

Early Screening, Faster Diagnosis

Among the tests performed on the CHC are disease tests which may prove invaluable in decreasing client costs associated with diagnosis, increasing speed of diagnosis, or improving medical outcomes. For example, many tests included on the CHC, such as the test for the neurological disease, degenerative myelopathy (DM) are adult-onset conditions which may not be observed in a dog until it has reached late adulthood. DM is a progressive disease caused by a genetic mutation in the canine SOD1 gene which can only be definitively diagnosed after death through histologic examination of the spinal cord because antemortem diagnostic methods fail to yield pathognomonic results. In addition ...

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 ...

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 ...

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 ...

Merle Coat Color- What Veterinarians Should Know

Merle Coat Color- What Veterinarians Should Know

While advancements in science, medicine, and agriculture have played a role in decreasing the relative importance of the dog in human survival, their importance as pets, companions, and surrogate family members may be greater than ever. Once more commonly selected for their athletic prowess and behavioral traits, the rise of dog fancying over the past 250 years has elevated the importance of canine aesthetics to previously unprecedented heights. As a result, dog breeders have historically gone to great lengths to produce dogs with unique phenotypic characteristics desirable to potential pet buyers. While most of these characteristics are simple, mendelian genetic traits without health concerns, some desirable and interesting traits such as the merle coat color pattern are unique to domestic animals and bring with them a complexity and potential health concerns that veterinarians should be aware of in their goal of facilitating canine health and wellbeing. 

An Interesting Mutation for an Interesting Haircoat

In 2006, Dr. Leigh Anne Clark and others identified a semi-dominant genetic mutation responsible for the merle coat color pattern commonly seen in numerous dog breeds including the Australian shepherd, collie, border collie, and dachshund. Merle coat color is marked by areas of normal, eumelanistic pigmentation ...

Who To Test? - Canine Autosomal Recessive Genetic Diseases

Who To Test? - Canine Autosomal Recessive Genetic Diseases

Genetics play an enormous role in the health of dogs walking through the doors of any veterinary hospital. However, the treatment of an animal with an inherited disease rather than proactive testing of the genetic mutations responsible for disease has been the traditional role of the veterinarian. With an increase in the availability of canine genetic disease testing and great improvements in the ease and convenience of ordering genetic testing through Paw Print Genetics, more and more dog breeders and their clients are having genetic testing performed preemptively and learning the benefits of these powerful technologies. As a veterinarian, understanding the basics of genetic testing and how genetic test results can be used to prevent and diagnose disease will keep you current and prepared for your clients as these technologies inevitably become a more significant part of clinical veterinary practice.

One of the more challenging but important aspects of canine genetic testing is deciding what recommendations to make when a dog or one of its relatives are found to be at risk for (or affected with) an inherited disease. Appropriate testing recommendations for the relatives of affected dogs may be crucial for prevention of additional affected puppies and identification of ...