Ullrich Congenital Muscular Dystrophy (Labrador Retriever Type 1)

Affected Genes: COL6A3
Inheritance: Autosomal Dominant
Mutation: chr25:48296579 (canFam4): G/A
Breed(s): Australian Labradoodle, Labradoodle, Labrador Retriever

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Common Symptoms

Ullrich Congenital Muscular Dystrophy (Labrador Retriever Type) is an inherited muscle disease in dogs. Affected dogs present at around 3 to 4 months of age with deformed limbs and hyperflexion of the joints, most notably of the wrist (carpus) and ankle (hock) giving the dog a flatfooted stance. Affected dogs may develop muscle Atrophy over time and have an abnormal gait. The disease is slowly progressive, and dogs can live many years before the disease becomes severe enough to warrant humane euthanasia.

Testing Tips

Genetic testing of the COL6A3 gene will reliably determine whether a dog is a genetic Carrier of Ullrich Congenital Muscular Dystrophy (Labrador Retriever Type, variant 1). This disease is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the COL6A3 gene mutation. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.


  • 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. Pathogenic variants in COL6A3 cause Ullrich-like congenital muscular dystrophy in young Labrador Retriever dogs. Neuromuscul Disord. 2020 May;30(5):360-367. [PubMed: 32439203]