Cardiomyopathy and Juvenile Mortality (Discovered in the Belgian Shepherd)

Cardiomyopathy and Juvenile Mortality is an inherited condition associated with the death of young puppies following nonspecific signs of illness. The associated genetic variant has been identified in the Belgian Shepherd.

Found in

1 in 3,400 dogs

in our testing

Key Signs

Variable and nonspecific, Vomiting, Dyspnea (trouble breathing), Muscle tremors, Early puppy death

Age of Onset

At birth

Present at birth


Autosomal Recessive

For autosomal recessive disorders, dogs with two copies of the variant are at risk of developing the condition. Dogs with one copy of the variant are considered carriers and are usually not at risk of developing the disorder. However, carriers of some complex variants grouped in this category may be associated with a low risk of developing the disorder. Individuals with one or two copies may pass the disorder-associated variant to their puppies if bred.

Likelihood of the Condition

High likelihood

At risk dogs are highly likely to show signs of this disease in their lifetime.

What to Do

Here’s how to care for a dog with Cardiomyopathy and Juvenile Mortality

Partner with your veterinarian to make a plan regarding your dog’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.

For Veterinarians

Here’s what a vet needs to know about Cardiomyopathy and Juvenile Mortality

Cardiomyopathy and Juvenile Mortality is an inherited condition associated with early puppy death following a short period of nonspecific signs of illness. Affected puppies may appear to have normal development during the first weeks of life. However, near the ages of 6 to 8 weeks old, affected puppies can present with vomiting, dyspnea (trouble breathing), tremors, twitching, urinary and fecal incontinence, or sudden death. Radiographs of affected puppies may show a hypoplastic (narrow) trachea or cardiomegaly (an enlarged heart). Postmortem examinations may also show cardiomegaly as well as abnormalities of other organs, particularly the liver, pancreas, spinal cord or brain. Cause of death in affected puppies is often thought to be due to degenerative changes to the heart which lead to heart failure.

Therapy is limited to symptomatic treatments and general supportive care. The average prognosis is considered poor for affected dogs and sudden death is possible at a young age.

For Breeders

Planning to breed a dog with this genetic variant?

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disorder is autosomal recessive, meaning two copies of the variant are needed for a dog to be at an elevated risk for being diagnosed with the condition. A carrier dog with one copy of the Cardiomyopathy and Juvenile Mortality (Discovered in the Belgian Shepherd) variant can be safely bred with a clear dog with no copies of the Cardiomyopathy and Juvenile Mortality (Discovered in the Belgian Shepherd) variant. About half of the puppies will have one copy (carriers) and half will have no copies of the variant. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. However, given the carrier rate of the variant in the Belgian Shepherd population, there is importance for keeping healthy carriers in the breeding program by breeding them to dogs that tested clear (zero copies) of the variant. Please note: It is possible that disorder signs similar to the ones associated with this Cardiomyopathy and Juvenile Mortality variant could develop due to a different genetic or clinical cause.

Technical Details

Gene YARS2
Variant G>A
Chromosome 27
Coordinate 16,157,324

All coordinates reference CanFam3.1

References & Credit

Credit to our scientific colleagues:

Gurtner, C., Hug, P., Kleiter, M., Köhler, K., Dietschi, E., Jagannathan, V., Leeb, T. (2020). YARS2 Missense Variant in Belgian Shepherd Dogs with Cardiomyopathy and Juvenile Mortality. Genes (Basel), 11(3), 313. View the article