The American Veterinary Medical Association convention went virtual this year, and one of the topics discussed was that a greater understanding of how genetic diseases occur can help vets prevent and mitigate their effects in our pets.

The speaker, Dr. Jerold Bell, a veterinarian and geneticist at Tufts University, said that many of the most common genetic diseases appeared in dogs and cats in the distant past, before modern breeds were developed, which is why we see them across breeds and in mixed breed animals.

The most common hereditary disorders in dogs are:

• Allergies
• Hip and elbow dysplasia
• Cancers (lymphoma, hemangiosarcoma, mast cell tumor, osteosarcoma)
• Patella luxation
• Bladder stones
• Hypothyroidism
• Mitral valve heart disease
• Inflammatory bowel disease
• Diabetes mellitus
• Retained testicles
• Umbilical hernias

In cats, the most common hereditary diseases are:

• Inflammatory cystitis
• Feline urological syndrome
• Diabetes mellitus
• Lymphoplasmocytic gingivostomatitis (mouth and gum disease)
• Bladder stones
• Allergies
• Eosinophilic skin disease
• Inflammatory bowel disease

According to veterinary geneticists, the primary cause of these diseases is not inbreeding, but the lack of selection against these harmful conditions.  In other words, a line of sires that have certain desirable traits may also be carriers of undesirable health problems.

“If we don’t select for healthy parents to produce offspring, then we have no expectation of health in those offspring,” Dr. Bell said. “Not selecting for health is selecting for disease, and we need to understand that and pass that on to our breeder clients.”

Dr. Bell points to the problem of brachycephalic obstructive airway syndrome in certain popular dog breeds like Pugs and French Bulldogs as an example.  When breeders and clients favor extreme traits like flattened muzzles, they also promote poor health conditions associated with those traits.

“Moderation away from extremes that cause disease should be the guiding principle in breeding,” Dr. Bell noted, and in judging dog shows.

He notes that while mixed breed animals can also suffer from inherited diseases, they are less likely to have rare and complex breed specific health problems.

However, the currently popular trend of “designer” mixed breeds can result in the offspring inheriting multiple genetic health problems from both purebred parents (a combination of dental, heart, and joint disease, for example).

Interested in learning more about the genetic health problems of different dog breeds?  Check out our blog post on the topic HERE.