Muscular Dystrophy (Discovered in the Labrador Retriever) Variant 1

Muscular Dystrophy is a severe disorder that causes muscle degeneration and weakness due to the formation of excess connective tissue in the muscle. This variant (UCMD) was discovered in the Labrador Retriever.

Key Signs

Angular limb deformity, Carpal hyperflexion, Joint laxity in distal limbs

Age of Onset

0 to 2 yrs

Juvenile onset

Inheritance

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 UCMD

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 UCMD

Clinical signs of the disease appear at around 4-5 months of age, and include carpal and tarsal hyperflexion, abnormal joint angulation, muscle wasting and gait abnormalities. The disease progresses slowly, and dogs may maintain ability to ambulate. Mentation of affected dogs generally remains normal. Blood chemistry can show persistent, marked elevation in serum creatine kinase (CK) concentrations and mild-moderate increases in ALT. Histopathology may show general signs of muscular dystrophy and endomysial fibrosis, and immunofluorescent staining for Collagen VI will show an absence of staining.

As there is no cure for this disorder, therapy is limited to symptomatic treatments and general supportive care. Ambulation and ability to support weight will likely be significant factors in survival and quality of life considerations.

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 Congenital Muscular Dystrophy (Discovered in the Labrador Retriever) variant can be safely bred with a clear dog with no copies of the Congenital Muscular Dystrophy (Discovered in the Labrador Retriever) 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. Please note: It is possible that disorder signs similar to the ones associated with this CMD variant could develop due to a different genetic or clinical cause.

Technical Details

Gene	COL6A3
Variant	G>A
Chromosome	25
Coordinate	48,014,962

All coordinates reference CanFam3.1

Shop now

References & Credit

Credit to our scientific colleagues:

Bolduc V, Minor KM, Hu Y, Kaur R, Friedenberg SG, Van Buren S, Guo LT, Glennon JC, Marioni-Henry K, Mickelson JR, Bönnemann CG, Shelton GD (2020). Pathogenic variants in COL6A3 cause Ullrich-like congenital muscular dystrophy in young Labrador Retriever dogs. Neuromuscul Disord. 2020 May;30(5):360-367. View the article