Genetic Testing!!
We wish the genetic testing could cover every health condition a Yorkie could have but at this time it does not. The labs are working on developing the testing for more. For now it covers 5 Yorkshire Terrier conditions.
For more information please scroll down!
Genetic testing is becoming more and more available for breeders.
Although it is expensive it is worth the investment for us.
I feel it is most important to know the health genetics of my dogs so I can be sure my puppies are not "at risk" for or "Affected" by certain genetic diseases/conditions.
In order for a puppy to be "at risk/affected" for one of the health conditions listed, both parents must pass on the gene for the condition. (Please see the picture above.)
If we know the genetics of our breeding dogs we know whom we can breed with whom to produce puppies who are not at risk!
Not all health conditions can be checked with DNA. There are some structural conditions that come out of nowhere even when parents and grandparents do not have the condition. Conditions like Luxating Patellas, Open Fontanels, Trachea problems and Legg Calves Perthes Disease, can be seen in dogs from parents who are perfectly fine.
There is no genetic test for liver shunt which can affect small dogs especially yorkies. It can show up out of the blue and from the research I have done on this condition, not much is known about how a puppy ends up with it, or what the genetic connection is, if there is in fact a genetic connection.
Responsible breeders will remove the parents of a liver shunt puppy from their breeding programs and have them neutered/spayed. I spoke to one of the DNA labs, Embark, and there is no information available. Continuing to use these parents for breeding, even with other dogs, would be taking a huge chance of producing another liver shunt puppy.
When you purchase a puppy you are taking a chance on him/her, as you are with any pet no matter what breed you decide on. All breeds have their own issues.
I can't guarantee my puppies against everything out there, I can only do my best.
The lab tested for over 170 genetic health conditions and they are finding new variants all the time. It is impossible to expect a puppy to be 100% perfect. We do our best with the help of Embark and my Vet, to make the best decisions when deciding who to breed.
Although it is expensive it is worth the investment for us.
I feel it is most important to know the health genetics of my dogs so I can be sure my puppies are not "at risk" for or "Affected" by certain genetic diseases/conditions.
In order for a puppy to be "at risk/affected" for one of the health conditions listed, both parents must pass on the gene for the condition. (Please see the picture above.)
If we know the genetics of our breeding dogs we know whom we can breed with whom to produce puppies who are not at risk!
Not all health conditions can be checked with DNA. There are some structural conditions that come out of nowhere even when parents and grandparents do not have the condition. Conditions like Luxating Patellas, Open Fontanels, Trachea problems and Legg Calves Perthes Disease, can be seen in dogs from parents who are perfectly fine.
There is no genetic test for liver shunt which can affect small dogs especially yorkies. It can show up out of the blue and from the research I have done on this condition, not much is known about how a puppy ends up with it, or what the genetic connection is, if there is in fact a genetic connection.
Responsible breeders will remove the parents of a liver shunt puppy from their breeding programs and have them neutered/spayed. I spoke to one of the DNA labs, Embark, and there is no information available. Continuing to use these parents for breeding, even with other dogs, would be taking a huge chance of producing another liver shunt puppy.
When you purchase a puppy you are taking a chance on him/her, as you are with any pet no matter what breed you decide on. All breeds have their own issues.
I can't guarantee my puppies against everything out there, I can only do my best.
The lab tested for over 170 genetic health conditions and they are finding new variants all the time. It is impossible to expect a puppy to be 100% perfect. We do our best with the help of Embark and my Vet, to make the best decisions when deciding who to breed.
Degenerative Myelopathy (SOD1A)
Brain and Spinal Cord (Neurologic)
Gene: SOD1
Inheritance type: recessiveA disease of mature dogs, this is a progressive degenerative disorder of the spinal cord that can cause muscle wasting and gait abnormalities. Affected dogs do not usually show signs until they are at least 8 years old, where the first signs of neural degeneration appear in the nerves that innervate the hind limbs. You may notice your dog scuffing the tops of his or her hind paws, or walking with a hesitant, exaggerated gait. In advanced cases, lower motor neurons are also affected leading to weakness or near-paralysis of all four legs and widespread muscle wasting. Given the advanced age at the time of onset, the treatment for DM is aimed towards making your dog comfortable in his or her old age and includes lifestyle changes and physical therapy. SOD1 codes superoxide dismutase, an enzyme important in neutralizing free radicals and reactive oxygen species, both of which are produced as a byproduct of cell metabolism. If not neutralized, these are injurious to the cell and will cause premature cell death. The first system to show effects of this is the nervous system given the highly specialized and delicate nature of these cells. Please note that these mutations are reported to have incomplete penetrance: that is, while a dog with two copies of this mutation has a much greater chance of developing DM than a dog with one copy of the mutation, or none at all, other genetic and environmental factors will also contribute to whether your dog develops DM.
Brain and Spinal Cord (Neurologic)
Gene: SOD1
Inheritance type: recessiveA disease of mature dogs, this is a progressive degenerative disorder of the spinal cord that can cause muscle wasting and gait abnormalities. Affected dogs do not usually show signs until they are at least 8 years old, where the first signs of neural degeneration appear in the nerves that innervate the hind limbs. You may notice your dog scuffing the tops of his or her hind paws, or walking with a hesitant, exaggerated gait. In advanced cases, lower motor neurons are also affected leading to weakness or near-paralysis of all four legs and widespread muscle wasting. Given the advanced age at the time of onset, the treatment for DM is aimed towards making your dog comfortable in his or her old age and includes lifestyle changes and physical therapy. SOD1 codes superoxide dismutase, an enzyme important in neutralizing free radicals and reactive oxygen species, both of which are produced as a byproduct of cell metabolism. If not neutralized, these are injurious to the cell and will cause premature cell death. The first system to show effects of this is the nervous system given the highly specialized and delicate nature of these cells. Please note that these mutations are reported to have incomplete penetrance: that is, while a dog with two copies of this mutation has a much greater chance of developing DM than a dog with one copy of the mutation, or none at all, other genetic and environmental factors will also contribute to whether your dog develops DM.
Hyperuricosuria and Hyperuricemia or Urolithiasis (SLC2A9)
Kidney and Bladder (Urinary)
Gene: SLC2A9 (Exon 5)
Inheritance type: recessiveThis condition causes kidney and bladder stones composed of urate; if caught early, it is responsive to dietary management. Uric acid is an intermediate of purine metabolism. In most dogs, uric acid is converted to allantoin, an inert substance that is then excreted in the urine. Dogs with HUU have defects in the pathway that converts uric acid to allantoin. As such, uric acid builds up, crystallizes and forms urate stones in the kidney and bladder. While hyperuricemia in other species (including humans) can lead to painful conditions such as gout, dogs do not develop systemic signs of hyperuricemia. Urate stones are invisible on X-rays and must be diagnosed by a veterinarian via ultrasound or urine sediment analysis. If left undiagnosed, bladder stones can lead to urinary obstruction, which can be life-threatening.
Kidney and Bladder (Urinary)
Gene: SLC2A9 (Exon 5)
Inheritance type: recessiveThis condition causes kidney and bladder stones composed of urate; if caught early, it is responsive to dietary management. Uric acid is an intermediate of purine metabolism. In most dogs, uric acid is converted to allantoin, an inert substance that is then excreted in the urine. Dogs with HUU have defects in the pathway that converts uric acid to allantoin. As such, uric acid builds up, crystallizes and forms urate stones in the kidney and bladder. While hyperuricemia in other species (including humans) can lead to painful conditions such as gout, dogs do not develop systemic signs of hyperuricemia. Urate stones are invisible on X-rays and must be diagnosed by a veterinarian via ultrasound or urine sediment analysis. If left undiagnosed, bladder stones can lead to urinary obstruction, which can be life-threatening.
L-2-Hydroxyglutaricaciduria (L2HGDH)
Brain and Spinal Cord (Neurologic)
Gene: L2HGDH
Inheritance type: recessiveCurrently there is no definitive treatment for L2HGA; rather, the condition is managed with anti-seizure and anti-anxiety medications. A rare metabolic disorder, this can cause seizures and behavior changes in affected dogs and usually requires medical management of these symptoms. Behavior changes can range from loss of trained behavior to hyperactivity to increased aggression, while seizures can vary in severity and duration. Affected dogs can experience seizures, behavior changes, or both. Definitive diagnosis of L2HGA involves testing blood, urine, cerebrospinal fluid, and/or other fluids and tissues for elevated levels of L-2-hydroxyglutaric acid. L2HGA was first identified in Staffordshire Bull Terriers and so is also known as “Staffy Cramp;" affected Staffordshire Bull Terriers present as early as 4 months and as old as 6 years with progressive neurologic symptoms. L2HGDH encodes the enzyme L-2-hydroxyglutarate dehydrogenase, which breaks down L-2-hydroxyglutarate. Buildup of L-2-hydroxyglutarate is known to induce oxidative stress, though the exact mechanism by which it causes the neurologic symptoms of L2HGA is unknown.
Brain and Spinal Cord (Neurologic)
Gene: L2HGDH
Inheritance type: recessiveCurrently there is no definitive treatment for L2HGA; rather, the condition is managed with anti-seizure and anti-anxiety medications. A rare metabolic disorder, this can cause seizures and behavior changes in affected dogs and usually requires medical management of these symptoms. Behavior changes can range from loss of trained behavior to hyperactivity to increased aggression, while seizures can vary in severity and duration. Affected dogs can experience seizures, behavior changes, or both. Definitive diagnosis of L2HGA involves testing blood, urine, cerebrospinal fluid, and/or other fluids and tissues for elevated levels of L-2-hydroxyglutaric acid. L2HGA was first identified in Staffordshire Bull Terriers and so is also known as “Staffy Cramp;" affected Staffordshire Bull Terriers present as early as 4 months and as old as 6 years with progressive neurologic symptoms. L2HGDH encodes the enzyme L-2-hydroxyglutarate dehydrogenase, which breaks down L-2-hydroxyglutarate. Buildup of L-2-hydroxyglutarate is known to induce oxidative stress, though the exact mechanism by which it causes the neurologic symptoms of L2HGA is unknown.
Primary Lens Luxation (ADAMTS17)
Eyes (Ophthalmologic)
Gene: ADAMTS17
Inheritance type: additiveThis surgically correctable condition causes the lens to spontaneously detach from its normal residence within the pupil, leading to reduced visual acuity and irritation to the surrounding tissues. The lens is suspended within the pupil by numerous small fibers that stretch between it and a ring of muscle within the iris (which allows your pupil to dilate and shrink to accommodate light). If these fibers rupture, the lens essentially falls out of the pupil. You can visually appreciate the lens luxation by peeking in your dog's pupil: almost always, the dislodged lens can be seen as a clear half moon either in front of or in back of the iris. Please note that while Embark tests for PLL, which has a known genetic basis, secondary lens luxation can be caused by a number of conditions including trauma, glaucoma, or certain metabolic diseases.
Eyes (Ophthalmologic)
Gene: ADAMTS17
Inheritance type: additiveThis surgically correctable condition causes the lens to spontaneously detach from its normal residence within the pupil, leading to reduced visual acuity and irritation to the surrounding tissues. The lens is suspended within the pupil by numerous small fibers that stretch between it and a ring of muscle within the iris (which allows your pupil to dilate and shrink to accommodate light). If these fibers rupture, the lens essentially falls out of the pupil. You can visually appreciate the lens luxation by peeking in your dog's pupil: almost always, the dislodged lens can be seen as a clear half moon either in front of or in back of the iris. Please note that while Embark tests for PLL, which has a known genetic basis, secondary lens luxation can be caused by a number of conditions including trauma, glaucoma, or certain metabolic diseases.
Progressive Retinal Atrophy - prcd Progressive rod-cone degeneration (PRCD Exon 1)
Eyes (Ophthalmologic)
Gene: PRCD Exon 1
Inheritance type: recessiveThis retinal disease causes progressive, non-painful vision loss. The retina contains the cells, photoreceptors, that collect information about light: that is, they are the very beginning of how we see. There are two types of photoreceptors: rods, which gather information about light intensity and are the major contributors to night vision, and cones, which distinguish color and are the major contributors to day vision. In nearly all forms of PRA, the rod cells are affected first, leading to night blindness. They are followed by the cone cells, leading to day blindness. The mechanisms by which the photoreceptors degenerate vary depending on the specific mutation that causes PRA. However, the readout is the same: the dog experiences a slow loss of vision, often leading to complete blindness. PRA is a subtle disease: most owners do not even know that their dog has gone blind--you may notice that your dog is reluctant to go down the stairs, or bumping into door frames or corners, or taking a very long time to fetch a ball or toy. A peek at your dog’s eyes in bright light may also reveal a sluggish pupillary constriction, because the retina is no longer telling your pupils that it is letting in too much light; however, definitive diagnosis of PRA requires a trip to the vet. Because of the slow progression of PRA, most dogs adapt very well to their condition. Over time, affected dogs can develop cataracts, thought to be due to buildup of reactive oxygen species and other toxic metabolites released from the degenerating retinal cells. This can lead to other complications and requires close monitoring in consultation with your vet.
Eyes (Ophthalmologic)
Gene: PRCD Exon 1
Inheritance type: recessiveThis retinal disease causes progressive, non-painful vision loss. The retina contains the cells, photoreceptors, that collect information about light: that is, they are the very beginning of how we see. There are two types of photoreceptors: rods, which gather information about light intensity and are the major contributors to night vision, and cones, which distinguish color and are the major contributors to day vision. In nearly all forms of PRA, the rod cells are affected first, leading to night blindness. They are followed by the cone cells, leading to day blindness. The mechanisms by which the photoreceptors degenerate vary depending on the specific mutation that causes PRA. However, the readout is the same: the dog experiences a slow loss of vision, often leading to complete blindness. PRA is a subtle disease: most owners do not even know that their dog has gone blind--you may notice that your dog is reluctant to go down the stairs, or bumping into door frames or corners, or taking a very long time to fetch a ball or toy. A peek at your dog’s eyes in bright light may also reveal a sluggish pupillary constriction, because the retina is no longer telling your pupils that it is letting in too much light; however, definitive diagnosis of PRA requires a trip to the vet. Because of the slow progression of PRA, most dogs adapt very well to their condition. Over time, affected dogs can develop cataracts, thought to be due to buildup of reactive oxygen species and other toxic metabolites released from the degenerating retinal cells. This can lead to other complications and requires close monitoring in consultation with your vet.
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DNA testing for breed type is not Accurate, especially for European Dogs. Due to the limited data collected on European dogs (Yorkshire Terriers in this case), we cannot guarantee any DNA tests regarding breed.
A message from Embark
"A DNA breed test cannot be used to certify a dog as a "purebred". This is because "purebred" status is not itself a scientific designation, but includes human-defined registration status and pedigree records indicating all of a dog’s ancestors were documented as purebred as well. While the term "purebred" is often associated with "single breed", this is not actually the same thing. As such, no breed percentage can make a dog purebred—that's up to registry bodies to determine.
Embark's DNA testing can generally inform on 3-4 generations of ancestry, which even for registered dogs will in some cases identify some DNA from another breed, often a closely related breed. This can occur for a variety of reasons, and these results do not affect the dog's registration or purebred status, because as stated earlier "purebred status" is not a scientific designation or dependent upon DNA ancestry results."
See the article, and letter from Mars Lab, concerning Breed type DNA below.
"A DNA breed test cannot be used to certify a dog as a "purebred". This is because "purebred" status is not itself a scientific designation, but includes human-defined registration status and pedigree records indicating all of a dog’s ancestors were documented as purebred as well. While the term "purebred" is often associated with "single breed", this is not actually the same thing. As such, no breed percentage can make a dog purebred—that's up to registry bodies to determine.
Embark's DNA testing can generally inform on 3-4 generations of ancestry, which even for registered dogs will in some cases identify some DNA from another breed, often a closely related breed. This can occur for a variety of reasons, and these results do not affect the dog's registration or purebred status, because as stated earlier "purebred status" is not a scientific designation or dependent upon DNA ancestry results."
See the article, and letter from Mars Lab, concerning Breed type DNA below.
The Benefits and Pitfalls of DNA Tests
By Nancy E. Halpern, D.V.M.
on February 26, 2017
POSTED IN DOG BREEDING, LABORATORY TESTING, U.S. DEPARTMENT OF AGRICULTURE (USDA)
Genetic testing in human and animal medicine has been used for some time, and shows great promise, when used judiciously. For example, genotyping the avian influenza virus and other pathogens has helped animal and human health officials understand the spread of pathogens so that measures can be implemented to prevent or mitigate such spread.
As reported by Greg Cima, “faster, cheaper genome sequencing is helping public health researchers identify the risks of drug resistance and medical treatment failure . . . The sequences also may help federal investigators find outbreak sources, by geographic location and species, as well as guide vaccine and antimicrobial development.” Finding risks in a flood of genetic data, JAVMA news Issues, Aug. 1, 2016. .
According to Dr. Jerold Bell, a small animal practitioner and adjunct professor at the Tufts University Cummings School of Veterinary Medicine, “companies are using diagnostics to determine what breeds exist in a mixed-breed dog . . . Some companies take it one step further and also tests for genes controlling body conformation and known disease-causing mutations.” M.S, Filippo, Genetic testing for pets quickly catching up to its human counterpart, AVMA press release, 8/8/2016.
Diagnostic test results are rarely dispositive, and the reliability of the results can be influenced by many factors, including, but not limited to: sample collection; quality control and quality assurance of test reagents; method and proficiency of testing; and interpretation of test results. Even tests performed by USDA-APHIS-approved laboratories that are part of the National Animal Health Laboratory Network, using reference materials and proficiency tests produced at the National Veterinary Services Laboratory that are accredited to international standards, must be interpreted by knowledgeable clinicians.
As a large animal veterinarian, when I received laboratory results from state or private laboratories that did not seem consistent with my patient’s clinical signs, I would consult with the laboratory director and other officials to discuss those inconsistencies. Sometimes, additional testing was warranted.
In some cases, the final results were never definitive.
As the Director, Division of Animal Health, New Jersey Department of Agriculture I was responsible for the oversight of the only animal health diagnostic laboratory in the State, and for interpreting laboratory results related to regulated and reportable diseases. That analysis started with the laboratory test results, and where the results appeared inconsistent with the clinical signs of the tested animal, an in depth review of the testing process from sample collection to results ensued.
Based on this extensive background and understanding of testing, I am concerned about the inappropriate use of certain genetic tests to refute the pedigree registration status of purebred dogs. As several courts have held, genetic testing is currently not dispositive of pedigree registration status.
See, e.g., Sandra Shines v. Furry Babies Stratford Square, Inc., No. 13-3592, slip op. at 9 (Ill. 18th Jud. Cir. Jan. 22, 2014) (finding DNA test results unreliable to support plaintiff’s claim that the cocker spaniel in dispute was a mixed breed).
Mars Veterinary, a business unit of Mars Petcare that sells a DNA genetic test called Wisdom Panel® warns that the test is not “intended to be used in any judicial proceedings” and further suggests that “If questions arise as to a purebred dog’s pedigree and breed ancestry, parentage testing through the AKC is the appropriate course of action. For this evaluation, the documented sire and/or dam are examined to ensure they were the genetic contributors to the dog in question.
If they are confirmed as the parents, their pedigree (and breed) is conferred onto the puppy.”
The purebred status of dogs is based on documentation confirming each dog’s lineage, required by the relevant breed canine breed registries—not the results of DNA testing. Similarly, ancestry DNA testing in humans could not be used to nullify the citizen status of a third-generation U.S. citizen, no matter what their genetic makeup reveals.
The proper use of genetic testing is reflected in AVMA’s new policy on “Inherited Disorders in Responsible Breeding of Companion Animals” which “supports research in genetic and inherited disorders to better educate the profession and breeders on identifying and minimizing inherited disorders in companion animal breeding programs.” K. Burns, AVMA passes policy on responsiblt pet breeding, JAVMAnews, Feb. 15, 2017.
Undoubtedly, genetic testing will be used as a increasingly important tool for pathogen tracking, disease control purposes, to help guide responsible dog breeders and to help identify the genetic make-up of mixed breed dogs, with unknown pedigree.
By Nancy E. Halpern, D.V.M.
on February 26, 2017
POSTED IN DOG BREEDING, LABORATORY TESTING, U.S. DEPARTMENT OF AGRICULTURE (USDA)
Genetic testing in human and animal medicine has been used for some time, and shows great promise, when used judiciously. For example, genotyping the avian influenza virus and other pathogens has helped animal and human health officials understand the spread of pathogens so that measures can be implemented to prevent or mitigate such spread.
As reported by Greg Cima, “faster, cheaper genome sequencing is helping public health researchers identify the risks of drug resistance and medical treatment failure . . . The sequences also may help federal investigators find outbreak sources, by geographic location and species, as well as guide vaccine and antimicrobial development.” Finding risks in a flood of genetic data, JAVMA news Issues, Aug. 1, 2016. .
According to Dr. Jerold Bell, a small animal practitioner and adjunct professor at the Tufts University Cummings School of Veterinary Medicine, “companies are using diagnostics to determine what breeds exist in a mixed-breed dog . . . Some companies take it one step further and also tests for genes controlling body conformation and known disease-causing mutations.” M.S, Filippo, Genetic testing for pets quickly catching up to its human counterpart, AVMA press release, 8/8/2016.
Diagnostic test results are rarely dispositive, and the reliability of the results can be influenced by many factors, including, but not limited to: sample collection; quality control and quality assurance of test reagents; method and proficiency of testing; and interpretation of test results. Even tests performed by USDA-APHIS-approved laboratories that are part of the National Animal Health Laboratory Network, using reference materials and proficiency tests produced at the National Veterinary Services Laboratory that are accredited to international standards, must be interpreted by knowledgeable clinicians.
As a large animal veterinarian, when I received laboratory results from state or private laboratories that did not seem consistent with my patient’s clinical signs, I would consult with the laboratory director and other officials to discuss those inconsistencies. Sometimes, additional testing was warranted.
In some cases, the final results were never definitive.
As the Director, Division of Animal Health, New Jersey Department of Agriculture I was responsible for the oversight of the only animal health diagnostic laboratory in the State, and for interpreting laboratory results related to regulated and reportable diseases. That analysis started with the laboratory test results, and where the results appeared inconsistent with the clinical signs of the tested animal, an in depth review of the testing process from sample collection to results ensued.
Based on this extensive background and understanding of testing, I am concerned about the inappropriate use of certain genetic tests to refute the pedigree registration status of purebred dogs. As several courts have held, genetic testing is currently not dispositive of pedigree registration status.
See, e.g., Sandra Shines v. Furry Babies Stratford Square, Inc., No. 13-3592, slip op. at 9 (Ill. 18th Jud. Cir. Jan. 22, 2014) (finding DNA test results unreliable to support plaintiff’s claim that the cocker spaniel in dispute was a mixed breed).
Mars Veterinary, a business unit of Mars Petcare that sells a DNA genetic test called Wisdom Panel® warns that the test is not “intended to be used in any judicial proceedings” and further suggests that “If questions arise as to a purebred dog’s pedigree and breed ancestry, parentage testing through the AKC is the appropriate course of action. For this evaluation, the documented sire and/or dam are examined to ensure they were the genetic contributors to the dog in question.
If they are confirmed as the parents, their pedigree (and breed) is conferred onto the puppy.”
The purebred status of dogs is based on documentation confirming each dog’s lineage, required by the relevant breed canine breed registries—not the results of DNA testing. Similarly, ancestry DNA testing in humans could not be used to nullify the citizen status of a third-generation U.S. citizen, no matter what their genetic makeup reveals.
The proper use of genetic testing is reflected in AVMA’s new policy on “Inherited Disorders in Responsible Breeding of Companion Animals” which “supports research in genetic and inherited disorders to better educate the profession and breeders on identifying and minimizing inherited disorders in companion animal breeding programs.” K. Burns, AVMA passes policy on responsiblt pet breeding, JAVMAnews, Feb. 15, 2017.
Undoubtedly, genetic testing will be used as a increasingly important tool for pathogen tracking, disease control purposes, to help guide responsible dog breeders and to help identify the genetic make-up of mixed breed dogs, with unknown pedigree.
