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Muscular Dystrophy-Dystroglycanopathy (Discovered in the Labrador Retriever)

Muscular Dystrophy-Dystroglycanopathy (MDD) is a type of muscular disorder that causes a failure to thrive in puppies. It is characterized by eating difficulties, poor weight gain, stunted growth, and weakness. The associated genetic variant has been identified in the Labrador Retriever.

Found in

1 in 67,000 dogs

in our testing

Key Signs

Failure to thrive, Eating difficulty, Stunted growth, Bow legged stance, Weakness

Age of Onset

At birth

Present at birth

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 MDD

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 MDD

Muscular Dystrophy-Dystroglycanopathy is a type of muscular dystrophy that is caused by defects in the modification of proteins by addition of sugars, also known as the cellular glycosylation process. Affected dogs will demonstrate signs of MDD as newborn puppies. Clinical signs can include difficulties feeding, poor weight gain, small stature, bow legged stance and weakness. Serum creatinine kinase (CK) values can be elevated in affected puppies. Histopathology can confirm the diagnosis of muscular dystrophy by showing the degenerative and regenerative changes consistent with a dystrophic phenotype. Due to poor suckling and difficulties eating, affected puppies experience a general failure to thrive and are unlikely to survive beyond a young age.

There is no curative treatment for the disorder. And, due to its severe and progressive nature, affected puppies are typically humanely euthanized by 6 weeks of age based on welfare grounds.

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 Muscular Dystrophy-Dystroglycanopathy (Discovered in the Labrador Retriever) variant can be safely bred with a clear dog with no copies of the Muscular Dystrophy-Dystroglycanopathy (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 Muscular Dystrophy-Dystroglycanopathy variant could develop due to a different genetic or clinical cause.

Technical Details

Gene LARGE
Variant C>T
Chromosome 10
Coordinate 30,357,716

All coordinates reference CanFam3.1

References & Credit

Credit to our scientific colleagues:

Shelton, G.D., Minor, K.M., Guo, L.T., Friedenberg, S.G., Cullen, J.N., Hord, J.M., … Mickelson, J.R. (2021). Muscular dystrophy-dystroglycanopathy in a family of Labrador retrievers with a LARGE1 mutation. Neuromuscul Disord, 31(11), 1169-1178. View the article