We have all heard of genetic disorders in humans. But can pets have genetic disorders too?
As pet parents, we want the best for our pets. Unfortunately, some pets are more prone to genetic disorders, with dogs having a longer list of possible genetic disorders.
Contrary to many people’s common assumption, genetic disorders are not purely a mixed-breed predisposition. Purebred cats and dogs can also suffer from genetic disorders.
Because of the heightened awareness of genetic defects by pet owners, breeders and veterinarians and the improved diagnostic capabilities in clinical practice, the number of hereditary diseases reported in small animals is growing rapidly. During the World Small Animal Veterinary Association World Congress proceedings in 2003, approximately 430 hereditary diseases in dogs and 180 disorders in cats had been adequately documented. Since then, it is estimated that more than a dozen new defects have been reported annually.
Although it is possible for any genetic defect to occur in any pet, many have been known to be more concentrated only in one family or breed. For a pet parent or animal practitioner, it can be a very daunting and nearly impossible task to remember all these genetic diseases.
What Causes Pets to Have Genetic Disorders?
Simply put, genetic disorders are caused by alteration of chromosomes or gene mutations. Mutations that cause disorders are heritable changes in the sequence of a pet’s genomic DNA. This alteration may alter the expression, function and structure of their coded protein.
Most genetic defects in our pets cause clinical signs early in their life. There are, however, congenital genetic disorders, meaning that the disorder is present at birth. Though these somewhat unspecific clinical signs may not be noticeable at birth, some disorders can cause specific, easily recognisable clinical manifestations that involve any part of a pet’s skeleton, lead to:-
- Disproportionate dwarfism- Pet’s with an average-size trunk and very short limbs, or a very short trunk and shortened, but disproportionately large limbs.
- Gait abnormalities- Abnormal walking where a pet is unable to walk in the usual way due to underlying conditions or problems with the legs and feet.
- Facial dysmorphia is a mental health condition where pets have a warped perception of the appearance of their face. This commonly includes distorted views on how their nose, skin and teeth look.
Common Genetic Disorders of Dogs and Cats
In order to reduce or altogether eliminate a genetic disorder, it is best to prevent further spread of the mutant gene in a family or in the entire breed. The best and most obvious way to do this is not to allow a pet with any genetic disease to breed. This is a simple and effective way to eliminate disorders with a dominant trait. For pets with recessively inherited disorders, however, discontinuing further breeding is not sufficient to markedly reduce the prevalence of a defect within that breed.
It is for this reason that in Australia, there are codes of practice for the breeding of animals with heritable defects that cause disease.
“The Prevention of Cruelty to Animals Act 1986 sets out offences for intentionally or recklessly breeding an animal with a heritable defect that causes disease as listed in the Schedule (‘the Schedule’) of the Act.
It is a cruelty offence to permit an animal to suffer from a heritable disease.
The code requires that animals with disease caused by a heritable defect must not be disposed of to another person without advice of the animal’s heritable defect status.”
Most Common Feline Genetic Disorders
Polycystic Kidney Disease (PKD)
Photo courtesy of VCA hospitals
This is an autosomal dominant disorder found in Himalayan and Persian cats. Many of these fur babies develop kidney failure, while some are lucky enough to only develop isolated cysts which do not greatly interfere with normal kidney function.
Before adding Persian and Himalayan cats to your family, it is advisable to have them tested by a veterinarian. Diagnostic testing in DNA positive cats includes a kidney function test and an abdominal ultrasound. A large percentage of all Persian cats carry the defective gene for PKD.
PKD positive cats and kittens should be sold or placed in forever homes with full disclosure about their disorder.
Unfortunately, PKD is also prevalent in other long-haired cat breeds of Persian and Himalayan ancestry.
- Increase in thirst and urination
- Decrease in appetite
- Weight loss
- High blood pressure
- Blood in the urine
Any changes in your cat could be a sign of disease and should be discussed with your veterinarian.
This is a dominantly inherited genetic disorder that progresses to heart failure in Ragdoll and Maine Coon cat breeds. Different mutations of the same gene for cardiomyopathy have been identified in both these cat breeds.
The Maine Coon cat breed also has a high incidence of orthopedic conditions as a result of abnormal development of one or both of their hip joints, causing instability and degeneration of the joints. There is also a rarely reported abnormality where a simple autosomal recessive trait is caused by loss of lower motor neurons in their spinal cord, causing them to show progressive weakness, muscular atrophy and a lack of balance during motion.
- Loss of appetite (anorexia)
- Difficulty breathing
- Inability to tolerate exercise or exertion.
- Short, rough, snapping breathing sounds (crackles)
- Weak pulse.
- Abnormal heart sounds (muffled, galloping rhythm, murmurs)
Most Common Canine Genetic Disorders
These include hemangiosarcoma, osteosarcoma, melanoma, lymphoma and mast cell cancers. Research focusing on dog breeds with genetic mutations in oncogenes (that promote cancer) and tumor suppressor cells (that act to prevent cancer) is still ongoing. In many of these cancers, testing the cells through a biopsy can allow a veterinarian to give a more accurate prognosis. This allows them to determine which drug therapies may be more effective and appropriate for treating your dog.
Cancer symptoms differ. If you do notice a change in your pet, please consult your vet.
Progressive Retinal Atrophy (PRA)
With this genetic disorder, the dog’s cells deteriorate over time and lead to blindness in the affected dog.
There are several inherited PRAs identified in dogs. It’s important to remember to practice selective breeding to eliminate dogs showing signs of PRA from the gene pool.
The most common progressive retinal atrophy is an autosomal recessive, late-onset progressive rod cone degeneration. The mutation that causes this dog genetic disorder occurred way before the differentiation of most breeds. For this reason, it is shared across a large variety of breed lines.
- Night blindness
- Bumping into things, especially in new environments
We hope this article has made you feel more informed about pet genetic disorders. In case you have more questions, be sure to download our PetsForever App on Playstore and Appstore where our team of vets, animal trainers, veterinary behaviourists, alternative healing providers and animal communicators will help you answer your questions and concerns.
Always consult with a vet if your pet is in pain or in distress.
Hereditary & Genetic Diseases Modern Diagnostics for Hereditary Disorders in Dogs and Cats. Accessed in April 2020.
Code of Practice for the Breeding of Animals with Heritable Defects that Cause Disease. Accessed in April 2021
5 Common Australian Dog Breeds that Suffer from Genetic Health Problems. Accessed in April 2021
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