What’s in your dog? Screening tests.

I have had a busy week and,  as always, one patient with a history of vomiting. Since that is a common complaint the challenge is to determine which ones are emergencies and which will pass. In further consultation with the owner, the invariable question arises,  “Is anything missing?" This patient, bright and alert, incidentally ate a golf glove approximately a month ago. So here are the lateral films. Do you see anything in the stomach.

Well, we did not know either since there is so much food in there. Yet I knew the white/ metal objects were not normal! Sooo, we gave an injection of apomorphine to induce vomiting and this is what we found. Surprise!!!! 

This is the golf glove consumed a month ago.  Just as I do not often know what an animal eats, I often do not know the genetic makeup of a patient, their allergic tendencies, and thus, their health risks.

What is out there for basic breed/genetic testing of Animals?

Royal Canin (yes, the food manufacturer) has a Genetic Health Analysis that reviews basic risks and breed background. I recently ran this on my own dog, Taco Belle and received these results. 

I am looking for more specific breed associated diseases. Is there a link?

Yes, I would look at the following sites. 

   http://www.offa.org/dna_alltest_b.html

https://www.vetstream.com/canis/corporate/html/Inheriteddiseases/Genetictestsforhereditarydiseases.htm

WHAT’S OUT THERE FOR CAT TESTING?

https://www.vgl.ucdavis.edu/services/cat/

What do veterinarians use for more specific genetic testing?

The Metabolic Genetic Disease Laboratory at the University of Pennsylvania 

http://research.vet.upenn.edu/penngen

Similarly Cornell's Comparative Coagulation Laboratory offers functional testing for many bleeding disorders 

http://ahdc.vet.cornell.edu/  

 Comparative Neuromuscular Laboratory in San Diego for neurological 

http://vetneuromuscular.ucsd.edu/

What are some of the laboratories that have skeptical results?

 Here is a pet store “off the shelf’ allergy test based on hair samples and saliva swabs collected from a 6 month old dog.  Scientifically, positive results of food allergy blood testing do not correlate with clinical food allergy in dogs. Note the disclaimer and allergy to white wine among other questionable results. 

With the known inaccuracy of food allergy blood testing in companion animals, it makes more sense to spend the pet owner’s time and funds on the prescription or home cooked hypoallergenic diet trial which is both diagnostic and potentially therapeutic. I wish we could call these tests "predatory health misinformation," sort of like predatory lending.

WHAT IS THE PROBLEM WITH VETERINARY vs HUMAN LABORATORIES?

Many upscale “veterinary laboratories” are not well regulated and thus are accountable to no one. I would be skeptical of any lab that is providing animal testing with no scientific VALIDATION of the results (from reputable sources). Testimonials alone are not evidence based medicine. Clearly the obvious question is, "where is the science and does it make sense?"

Betsy Sigmon DVM, Diplomate ABVP Canine & Feline 

Creature Comforts Animal Hospital PLLC

Cary, NC

My thanks for photos to Terry Seaks sharing Puffball the cat  and Tammy Butler sharing her Rescue Dog January staring at statue with the blog followers. Memphis Woodall is a repeat performance from last week now wearing antlers. 

WHAT’S IN YOUR PEDIGREE, PART 2, PUREBRED DOG

In the last blog entry, the passages center on the pedigree of my parents that leads to yours truly and her 5 siblings. Today I would like to add some “behind the scenes” recollections of the first time my Mom traveled to Kentucky from New York. As she became romantically engaged with my father, she realized his pedigree would not be the mint julep set, the white fences, or the Kentucky Thoroughbred horses grazing serenely in the background. When it came to meet her in-laws, the scenario was quite a “culture shock” way beyond her preconceived notions. Step 1: Uncle Lester came with a tractor to pull my father and mother out of the ditch, beside the dirt road, next to the barb wire fencing. As they sloshed back and forth toward the homestead on the muddy, rutted road, the expectation drops further: outhouse, no indoor plumbing. Step 2: Coming from a masters in human nutrition background at Cornell, the smell of ham hocks and beans cooking in the house was overwhelming.  Step 3: Sleeping on feed sacks and Sears catalog in the outhouse (substituted for toilet paper) she cried herself to sleep and hit the “reset” button of expectations.

Often with acquisitions of new pets, hidden agendas come with the territory of “forever homes."

WHEN ACQUIRING A PUREBRED DOG, WHAT ARE SOME FACTORS TO BE CONSIDERED?

There are normally many breeds that will fit close the requirement of a new pet family member. One site to consider by breed is http://ic.upei.ca/cidd/ or http://www.caninehealthinfo.org/breeds.html or http://www.offa.org/breedtests.html?btnSearch=Tests+by+Breed or http://idid.vet.cam.ac.uk/search.php  as a starting point. It is important that when the breed is less populated (and thus has low registration numbers by the AKC, if recognized at all), defects may not be well publicized or known.

HOW DOES A VETERINARIAN OR PET OWNER FIND A LABORATORY THAT PERFORMS SPECIFIC TESTING? What types of tests are available?

DNA testing has an advantage over other biochemical testing as it may be performed at any age, including newborn.   DNA can be extracted from any nucleated cells, e.g., blood, cheek swabs, hair follicle, semen, and even preserved tissue. The biggest reason for these tests is the results are available before placing the puppy in a new home, manifesting signs, or prior to breeding to avoid passing on the defect.

http://www.offa.org/dna_alltest_b.html

http://breedingbetterdogs.com/pdfFiles/articles/genetic.tests.by.breed.2012.pdf

https://www.vetstream.com/canis/corporate/html/Inheriteddiseases/Genetictestsforhereditarydiseases.htm

Inborn errors of metabolism tests, many of which are blood tests,  include all biochemical disorders due to a genetically determined, specific defect in the structure and/or function of a protein molecule within the body.  These defects can lead to bleeding disorders, muscle weakness, heart disease,   and unfortunately, premature death.

The Metabolic Genetic Disease Laboratory at the University of Pennsylvania offers such tests http://research.vet.upenn.edu/penngen. Similarly Cornell's Comparative Coagulation Laboratory offers functional testing for many bleeding disorders http://ahdc.vet.cornell.edu/ and the Comparative Neuromuscular Laboratory makes some functional and mostly histological analysis available for muscle and nerve disorders http://vetneuromuscular.ucsd.edu/.

AS A VETERINARY PRACTITIONER FOR OVER 33 YRS, WHAT IS ONE CONCERN FOR NEW OWNERS OF PUREBRED DOGS?

Many of the more frequently seen health issues: allergies, ear infections, dental disease, arthritis, and irritable bowel/inflammatory bowel disease do not have current, valid genetic testing to screen potential parents that potentiate the risk. Yet, these diseases result in very significant time, emotional, and financial costs for pet owners.

For example, Labrador Retrievers suffer more from debilitating elbow arthritis, dysplasia that hip dysplasia/arthritis, Yet many prospective owners are aware of the hip issues, only.

 TESTING MIXED BREED DOGS? IS THERE A NEED?

This question comes up occasionally in the exam room and was addressed in the previous blog. Having said that, there is no harm except to your wallet (avg. cost is $60 to $100) to obtain a cheek swab (see lab for specific instructions) to see what breeds are in your pet’s background. Remember the validity of the test results, are open to discussion. http://shop.dnamydog.com/ or http://www.wisdompanel.com/

In reality, few medical decisions for mixed breed animals are based on genetic breed screening.

Betsy T. Sigmon DVM, Hospital Director

Creature Comforts Animal Hospital

In memory of Molly, owned by Rick and Chris Vandenberg

What’s in Your Pedigree: Genetic Screening

                       

For those blog followers who have been clients of mine for almost 30 years, there has never been any question as to the lack of royal lineage in my background. My father hails from a whiskey bootlegging family in Western Kentucky. All gained riches during the Depression were followed by relatives serving jail time.  They made liquor runs from Nashville to Louisville and yonder.

  My Mother was the daughter of an architect and granddaughter of a German Presbyterian minister from New York City. They met at Cornell University where my mother worked in my father’s nutrition lab. The intersection of these 2 cultural background is “yours truly."

My dog, Taco Belle, was found in a trailer park in Zebulon, NC. Looking at her one would say she is a Dachshund/Chihuahua cross. Recovering since last week from a collapse disk at Lumbar vertebrae 1-2, her genetic framework makes her more prone to weakness in her mid- back area. I am happy to report she is improving with rest, pain medications, and strict exercise restriction. In her first year, I had sent out a new genetic screening blood test, advertising the benefits of genetic screening to better treat genetically linked disorders. Taco Belle’s test results stated Bassett Hound x Rhodesian Ridgeback (so much for the early genetic blood testing in 2007). It states the obvious:  test results are only as valid as the accuracy of the test (also called sensitivity and specificity).

Let’s look into some of the current genetic screening tests for pets.

WHAT IS THE BASIS FOR GENETIC SCREENING OF ANIMALS?

With natural selection, the "survival of the fittest," although a buzz word for healthy, truly has a genetic basis. Due to man’s interference, selecting for certain physical traits is reflective of man’s preference, not necessarily for the betterment of the animal. With greater than 120 biochemical/DNA screening tests for defects (and the list is growing), it is confusing for both owners and  veterinarians what are the proper background checks prior to purchase of a specific breed of cat or dog. The confusion is magnified with the new tendency towards “designer breed” crossing. Although touted to bring out the best in both parents, this breeding can increase the tendency of bad traits. For example, when both parents come from a breed known for allergies, the offspring, even though a mixed breed (outcross) may have an increased tendency to allergies as well. Basil D'Gerolamo pictured. 

SO WHAT ARE THE WAYS TO TEST FOR KNOWN DEFECTS?

Once beyond the physical exam, the following are important indicators of disease: physical exams, radiographs, and laboratory testing for genetic markers. 

WHAT IS ONE OF THE biggest fallacies of testing pets?

Many young, breeding stock pets will be examined and pronounced clear (phenotypically) on eye and orthopedic exams of many inherited conditions (via eye exams and radiographs). However many will as adults develop inherited eye and joint problems.

WHAT IS ONE EXAMPLE OF A GOOD SCREENING BLOOD TEST IN CATS?

Persians, Himalayans, and other cats with Persian ancestry should be screen for Polycystic Kidney Disease. It is a progressive, inherited disease that leads to cysts on the kidneys, renal failure, and death. By testing both the queen and tom (both parents) negative for the PKD1 gene prior to breeding, the risk in the kittens is eliminated. The list of breeds carrying this genetic disease is expanding. Otherwise the disease is diagnosed with ultrasound of the kidneys of cats at risk as early as 10 months of age.  In the past, up to 50% or more of Persian cats may have been affected by this disease. Sofi owned by Ian Fletcher pictured

http://www.icatcare.org/advice/polycystic-kidney-disease

IS THERE A GENERAL WEBSITE TO CHECK FOR GENETIC DISORDERS OF CATS?

http://www.icatcare.org/advice/cat-breeds

WHAT IS ANOTHER EXAMPLE OF A GENETICALLY SCREENED DISEASE?

Hypertrophic cardiomyopathy of Ragdoll and Maine Coon Cats is condition where the heart wall muscle thickens. By reducing the heart chamber size, less blood is pumped with each contraction. Thus it may to heart disease, blood clots, and often sudden death.

http://www.icatcare.org/advice/cat-health/hypertrophic-cardiomyopathy-hcm-and-testing

WHAT HAS MADE GENETIC TESTING SO MUCH EASIER FOR CAT BREEDERS?

Many tests of today are performed on cheek swab samples, rather than traditional bloodwork.

https://www.vgl.ucdavis.edu/services/cat/

Betsy Sigmon DVM, Diplomate American Board of Veterinary Practitioners, Canine & Feline