Know The Connection Between Breed And Disease

by Michael Forney

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Anyone who owns a dog (or a cat for that matter), hopefully expects to take their fur child to a veterinarian at least occasionally during its lifetime, for various reasons. In addition to wellness and preventive care, there are certain issues veterinary doctors treat more frequently. Nationwide Veterinary Pet Insurance released a 2016 report on the top ten most common medical conditions for which it received insurance claims (see chart on page 68). At the top of the list for dogs were skin allergies and other skin-related issues. Other common complaints include arthritis, dental disease, GI tract disease, urinary tract disease, and trauma. The take-home message is that dog owners can probably expect to make a vet visit for at least one of these conditions during their pet’s lifetime. Even more interesting, however, is that certain breeds of dogs are predisposed to having some of these diseases.

Why are some breeds predisposed to certain diseases?

If you are not already aware, every dog breed is different (crazy, right?). But why would some breeds be more likely to have one medical condition over another? Like human beings—perhaps even more importantly so—genetics play a large role in the likelihood that a dog will acquire certain diseases. Creating different breeds of dogs has made this fact even more apparent.

Genetics play a large role in the likelihood that a dog will acquire certain diseases.

Purebred dogs have a higher degree of genetic similarity due to inbreeding to select specific traits for each breed. Therefore, some gene variants, or genotypes (which may be potentially damaging), become more frequent within the population. For example, brachycephalic dog breeds have been selected to have a “desired” trait—e.g., short faces. Unfortunately, along with their cute, squashed faces, these dogs are more inclined to have a variety of conformational changes that can potentially negatively impact their health. Of course, other breeds of dogs are prone to their own issues as well.

Finally, the main point of the article: common diseases and the breeds in which they occur. This article is not written to chastise anyone on owning a purebred dog (I have a German shepherd, myself). Rather it is to help owners gain awareness of some of the diseases they might expect their dogs to develop over their lifetime and to hopefully prepare them for treatment.

Source: https://press8.petinsurance.com/articles/2016/march/nationwide-reveals-the-10-most-common-medical-conditions-for-dogs-and-cats

Types of Disease

Skin Disease: Allergic dermatitis

At the top of the list is skin allergies. Many breeds of dogs are predisposed for a variety of reasons to allergies. If you already have a dog with allergies, you may be aware that the three most common types of hypersensitivities in dogs are flea, food, and environmental allergies. So if your dog starts chewing at his paws, licking his belly, scratching, or shaking his ears, you might want to visit the vet. The doctor will want to rule potential causes and may suggest skin scrapings, swabs, and tape preps to rule out external parasites and look for the presence of bacteria or yeast. Some of the therapies may include medications or injections for itchiness, shampoos, mousses, flea and parasite prevention, and diet trials.

Commonly predisposed breeds: Labrador retrievers, golden retrievers, German shepherds, Shar-Peis, boxers, pit bulls, bulldogs, and many more

Dental Disease: Gingivitis/periodontitis

Many dog owners probably are aware of and may be concerned by their dog’s teeth (especially if they have bad breath). The bigger concern for veterinarians, however, is under the gum line. With chronic gingivitis and periodontitis, the fibers attaching teeth to jaw bone are broken down. The bone itself can disappear. This can lead to infection, pain, and tooth loss. This is an important reason to implement routine tooth care (e.g., brushing and dental chews) along with veterinary visits to evaluate your pup’s mouth. Anesthetic dental cleanings are important for taking X-rays to evaluate the bone, as well as for properly cleaning under the surface of the gums, depending on the severity of disease.

Commonly predisposed breeds: small breed dogs, e.g., Maltese, Chihuahua, miniature poodles, terrier breeds, pugs, bulldogs, etc.

Gastrointestinal Diseases

There are many diseases that can affect the GI tract, resulting in vomiting, diarrhea, or a combination of both. Of course, many causes are not related to breed such as dietary indiscretion (e.g., eating out of the garbage), toxin exposure, drugs, infection (e.g., parvovirus), and many others. Therefore, it is always a good idea to have your furry friend evaluated by a veterinarian if you see these signs. Listed below are some fairly uncommon diseases that have been shown to have breed predilections.

Esophageal Disorder: Hiatal hernia

This is a disease in dogs where the part of the esophagus located in the abdomen slides forward into the thoracic cavity. They will have regurgitation as a primary clinical sign generally associated with feeding times or excitement. Treatment usually involves medical management to protect the esophagus from damage due to acid reflux and surgery to prevent the esophagus from continuing to herniate.

Predisposed breeds: Brachycephalic dogs such as English bulldogs, Boston terriers, and French bulldogs are poster children for sliding hiatal hernias.

Liver Disease

Congenital portosystemic shunts (liver shunt)

Although not as common as many of the other described diseases, shunts are more likely to occur in certain breeds and will be noted at an early age. These dogs will often be smaller compared to littermates, less energetic, and may have neurologic signs. Diagnosis involves blood work and imaging—X-rays and ultrasound. Depending on the type of shunt, surgery may be possible. If not, medical therapies are available.

Predisposed breeds: Yorkies and other terriers, golden retrievers, Laborador retrievers, Irish wolfhounds

Chronic hepatitis

This disease may be caused by a variety of mechanisms and is less well understood. Clinical signs in dogs often include lethargy and weight loss. Generally, it will occur in middle-age to older dogs, as it is a chronic disease. Definitive diagnosis is based on liver biopsies; however, this is a more invasive procedure. Your veterinarian will likely recommend blood work at a minimum and may consider various medications to support the liver.

Predisposed breeds: Bedlington terrier, Dalmatian, English springer spaniel, Skye terrier, Labrador, cocker spaniel, Doberman, West Highland white terrier

Heart Disease

Myxomatous mitral valve degeneration (MMVD)

This disease has several names, including mitral valve endocardiosis and is one of the most common heart diseases in dogs. It affects the mitral valve, which separates the left atrium and ventricle of the heart and normally acts to prevent back flow of blood. With changes to the valve, blood flows less regularly, backs up, and causes changes to the chambers of the heart. Progression of the disease can ultimately lead to heart failure. If your veterinarian hears a murmur during your dog’s physical exam, she will likely recommend referral to a cardiologist for an echocardiogram to evaluate the heart. In some cases, dogs may be put on medications that have been shown to delay the onset of heart failure. To be less alarming, many dogs live with this disease their whole life and can be asymptomatic.

Predisposed breeds: Cavalier King Charles spaniels (poster child) and older small breed dogs

Orthopedic and Neurologic Diseases

When a dog becomes lame, whether in one limb or multiple limbs, your veterinarian will want to determine if the source is musculoskeletal or neurologic. They should perform a good physical exam and/or orthopedic and neurologic exam, depending on the signs and may consider further testing such as X-rays, blood work and ultrasound. Depending on the disease, they may even recommend referral to a specialist for further testing, therapies, or surgery.

Cranial Cruciate Ligament Rupture

This disease can cause dogs to become suddenly lame on either one or both of their hind limbs. The ligament that ruptures is in the stifle joint (knee) and normally acts to stabilize it. Surgery with an orthopedic specialist is usually recommended to removed damaged tissue from the joint space and stabilize the knee.

Predisposed breeds: Newfoundlands, Rottweilers, Labrador retrievers

Medially Luxating Patella

With this condition, the patella (or kneecap) luxates, or “pops out” of the groove it normally sits in. It is often an incidental finding, but can progress in severity, causing changes with time leading to arthritis and increased lameness. Depending on the grade of the condition, your veterinarian may recommend surgery with a specialist.

Predisposed breeds: small and toy breed dogs, such as Chihuahuas, terriers, shih tzu, toy poodles, Pomeranians, etc.

Intervertebral Disc Disease (IVDD)

There are different types of intervertebral disc disease and dogs present differently depending on the course of the disease. However, they all involve the cartilaginous discs that reside between each vertebrae, which normally act as cushions and provide flexibility. With these diseases, the disc can be damaged or bulged, which then causes compression or injury to the spinal cord. When this happens, the nerve fibers below the injury no longer function properly. Depending on the severity of injury, patients may lose motor or sensory function and hence their ability to walk. Dogs that suddenly go down either in their back legs or all four legs should be taken quickly to a veterinarian, since time can play an important role in recovery if surgery is deemed necessary to remove the damaged disc material. The surgery usually needs to be done by a specialist, and several diagnostic tests will need to be performed beforehand including blood work, urine tests, X-rays, ultrasound, and MRI. These tests are done to rule out diseases such as cancer, other systemic illnesses, and potential causes for the lameness other than IVDD.

Predisposed breeds: Dachshunds, corgis, pugs, cocker spaniels, beagles, German shepherds, Dobermans, giant-breed dogs—honestly, any breed. (Remember, there are different types of IVDD!)

Final Note

The aforementioned conditions do appear to have at least some genetic predisposition; however, please keep in mind that they can occur in any breed of dog. Additionally, the order in which breeds were listed was not particularly significant. As with any medically related article, my best advice is to make an appointment with your dog’s primary care veterinarian if you have any concerns.

Resources

Collins, L.M., Asher, L., Summers, J. & McGreevy, P. 2011. Getting priorities straight: risk assessment and decision-making in the improvement of inherited disorders in pedigree dogs. The Veterinary Journal. 189, 147–54.

Hensel, P., Santoro, D., Favrot, C., Hill, P. & Griffin, C. 2015. Canine atopic dermatitis: detailed guide for diagnosis and allergen identification. BMC Veterinary Research. 11, 196.

Leroy, G. 2011. Genetic diversity, inbreeding and breeding practices in dogs: results from pedigree analyses. The Veterinary Journal. 189, 177–82.

Watson, P. 2017. Canine breed-specific hepatopathies. Vet Clin Small Animal. 665–83. Veterinary Pet Insurance (VPI) https://press8.petinsurance.com/articles/2016/march/nationwide-reveals-the-10-most-common-medical-conditions-for-dogs-and-cats

VCA Rancho Mirage Animal Hospital located at 71-075 Highway 111, Rancho Mirage, CA. 760-346-6103. Visit vcaranchomirage.com

Cats and Genetic Disorders

As with dogs, any cat breed can develop health problems regardless of its breed, but some breeds may have a genetic predisposition to certain illnesses.

Diabetes mellitus

Burmese, Siamese, Norwegian Forest, Russian Blue and Abyssinian

Inflammatory bowel disease

Siamese and other Asian breeds

Polycystic kidney disease

Persian, Himalayans and other Persian-type breeds

Hypertrophic cardiomyopathy

Maine Coons and Ragdolls

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