Author archives: Casey Carl

Von Willebrand disease (vWD) is arguably the most well recognized canine blood clotting disorder. A common genetic mutation in the VWF gene (first described in the Doberman pinscher in 2001) has played a significant role in increasing the recognition of vWD as a cause of clotting problems in dogs¹. Genetic testing for this mild to moderate platelet disorder, known as vWD type 1 (vWD1 or vWDI), has played an important role in assisting veterinarians in diagnosis and in assisting breeders in identification of non-symptomatic carriers of the mutation prior to breeding. Since that time, dozens of other breeds have also been found to be affected by the same mutation. Thus, solidifying vWD as a potential concern for many dog lovers. In addition, other genetic mutations in the VWF gene have also been associated with more severe forms of von Willebrand disease (type 2 and type 3) in some breeds.

Despite the important role of testing some breeds for the identified vWD1 mutation, it is also important to keep in mind that hemostasis is an incredibly complex process involving multiple physiologic steps and the interaction of many protein clotting factors, various cell types, and endogenous molecules. In some breeds, other ...

To usher in 2022, Paw Print Genetics (PPG) has added 12 new canine disease and trait tests to expand upon the largest selection of canine genetic tests in the industry. However, because diseases seen in veterinary practice are not seen with equal frequency, here I will highlight five of the new test offerings for diseases that are among the most likely to be encountered in veterinary practice. 

Ataxia (Norwegian Buhund Type)¹- Norwegian Buhund

Ataxia (Norwegian buhund type), also known as cerebellar ataxia, is an early-onset autosomal recessive neurological disease affecting the Norwegian buhund. Dogs inheriting two copies of the associated KCNIP4 gene mutation present between three and five months of age with progressive neurological disease. Initial clinical signs are consistent with cerebellar ataxia, including wide-based stance, hypermetria, head tremors, and truncal sway. As the disease progresses, dogs are eventually unable to stand or walk without falling. Cerebellar degeneration is a common histopathological finding in affected dogs and dramatic reductions in cerebellar KCNIP4 protein have been described. The speed of disease progression is variable, but affected dogs are often euthanized due to quality-of-life concerns.

In one study, 19% out of 146 apparently healthy Norwegian buhunds tested carried one copy ...

By Casey R. Carl, DVM and Blake Ballif, PhD

A topic in veterinary genetic testing currently getting significant attention is the difference between direct and indirect genetic testing for mutations associated with various diseases and traits. Although both types of testing can play a useful role in determining a dog’s genetic health status, the use of indirect genetic testing comes with some additional caveats that need to be considered when selecting the best testing strategy for a particular dog.

Direct Genetic Testing

As the name indicates, direct genetic testing is a general term for any genetic testing technique which looks for the presence of the specific genetic variant (mutation) known to play a causal role in a particular disease or trait. Therefore, regardless of which genotyping technique used, test results obtained from direct testing identify the presence or absence of the specific mutation that has been associated with the disease or trait. Barring differences in quality of laboratory practices and test development, direct testing is therefore the ideal method to detect a specific mutation. Furthermore, identifying the precise causative mutation in a DNA sample from a dog allows one to draw appropriate conclusions about the implications of this mutation in this ...

2021 has been an exciting year for Paw Print Genetics (PPG) and canine genetic health. With the addition of 15 new genetic disease and trait tests in July 2021, PPG has now added more than 50 new canine test offerings this year alone! However, when it comes to specific genetic diseases, variability in the population size of affected breeds and the frequency of the associated mutations, means that some diseases are much more likely to be seen in veterinary hospitals than others.

Here we will highlight four new genetic disease tests offered at PPG for canine diseases common enough to be seen in general veterinary practice. In addition, we will briefly discuss PPG’s new web-based disease and coat color probability calculators which assist breeders and veterinarians in selecting ideal parents for producing healthy puppies in the coat colors and patterns desired.

Progressive Retinal Atrophy (Giant Schnauzer Type)¹- Giant Schnauzer, German Spitz, German Spitz Klein, Keeshond, Miniature Smooth and Longhaired Dachshund, Pomeranian

Progressive retinal atrophy (Giant Schauzer Type), also known as generalized PRA or PRA5, is an autosomal recessive form of PRA affecting the giant schnauzer and several other breeds. Dogs inheriting two copies of the associated NECAP1 gene ...

With the rapid expansion of feline and canine genetic disease testing popularity over the past several years, today it is more common than ever for veterinarians to be asked to interpret genetic test results for their clients and offer recommendations based upon the results. However, the team at Paw Print Genetics (PPG) realizes that genetic counseling has not been a traditional part of veterinary education. For this reason, PPG offers no-cost genetic consultations for veterinarians and veterinary staff to assist their clients with genetic questions. Here we will discuss some of the many factors to be considered when assisting the veterinary team with interpreting genetic test results, assessing disease risk, and making breeding recommendations for the 300+ genetic tests offered at PPG.

Disease Inheritance

Understanding exactly how a specific disease is inherited by offspring can alter your assessment of disease risk and recommendations for breeding. The most common inheritance types discussed in animal genetics are autosomal recessive, autosomal dominant, and X-linked recessive inheritance. However, less common inheritance patterns may also be seen for some animal diseases. Disease risk in animals inheriting one copy of a disease-associated mutation varies based upon the specific mode of inheritance. For example, dogs carrying one ...

As of January 2021, Paw Print Genetics (PPG) is proud to offer 44 new inherited disease tests for the canine health and breeding community. While these new tests are associated with diseases identified in dozens of breeds, the population size of each breed and the relative frequency of these mutations in those populations mean that some of these diseases are much more likely to be seen in clinical veterinary practice than others. Here we will highlight five diseases from the recent PPG test additions that are among those most likely to be diagnosed in the veterinary hospital setting.

Cerebellar Degeneration- Old English Sheepdog and Gordon Setter¹

A genetic mutation in the canine RAB24 gene is associated with a juvenile-onset, autosomal recessive form of cerebellar degeneration (CD) in two seemingly disparate breeds, the Old English Sheepdog (OES) and Gordon Setter (GS). Also referred to as hereditary ataxia or cerebellar abiotrophy (CA), CD presents between 6 months and 4 years of age with progressive neurological dysfunction due to degeneration of cerebellar neurons, especially Purkinje neurons. Coordinated movement becomes progressively more difficult as the disease progresses and can include intention tremors, ataxia, and a stiff, high-stepping gait (hypermetria). Affected dogs are often ...

Canine progressive retinal atrophy (PRA) is a group of inherited eye diseases which are among the most common causes of inherited blindness in domestic dogs. Extensive study and characterization of the various PRAs have led to the discovery of well over a dozen different genetic mutations in many different genes which can now be identified to help prevent, predict, or diagnose PRA in many breeds. However, complicated PRA naming schemes and the breed-specific nature of the PRA tests can make it challenging for dog breeders or veterinarians to select the correct test for the dog in front of them.  

Multiple Genes, Similar Clinical Findings

The known underlying mutations associated with the various forms of PRA are found in a wide variety of different genes. Thus, highlighting the complexity of the biological pathways involved in the development and ongoing maintenance of the eyes. PRAs are marked by the abnormal development and/or the gradual degeneration of rod and cone photoreceptor cells of the retina. Each type of PRA may display variation in the age of onset, speed of disease progression, and the relative rates at which each of the two photoreceptor types are destroyed. However, when it comes to clinical ...

The leaves are falling and the pumpkins are reaching their proper jack ‘o lantern size. Soon children everywhere will be dining on a steady diet of Halloween candy while many of us adults relive our youth by taking full advantage of the one day every year we can pretend to be someone (or something) else. Though many dogs also enjoy the excitement that Halloween brings, this time of year can present additional hazards and stressors for our canine friends.

Alcohol and Junk Food

Although Halloween parties in 2020 are likely to be much different than in years past, our opportunistic dogs are still likely to find themselves around more potentially dangerous food and drink than is typical in their daily lives. A cocktail placed at dog height or a single plate of carelessly placed food have been known to ruin more than one celebratory day.

Alcoholic beverages are a particular concern for dogs during holidays and celebrations. Dogs under the influence of alcohol tend to suffer the same consequences as their overindulgent human counterparts including drowsiness, vomiting, lack of coordination, and slow reflexes. Dogs consuming toxic levels of alcohol may experience depression, breathing and heart rate abnormalities, collapse, low ...

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 ...

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 ...