Bernard-Soulier Syndrome

Other Names: Bernard-Soulier Syndrome Type C, BSS
Affected Genes: GP9
Inheritance: Autosomal Recessive
Mutation: chr20:3053455-3055914 (canFam4): 2460 bp deletion

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Common Symptoms

Bernard-Soulier Syndrome is an inherited bleeding disorder affecting cocker spaniels. Affected dogs typically present between 2 to 4 years of age with variable signs of bleeding. Commonly, this will be prolonged bleeding and formation of a hematoma, or large blood clot, after a routine blood draw during a veterinary exam. Other signs can include episodes of bleeding in the mouth around the gums and nosebleeds. Veterinary findings of dogs affected with Bernard-Soulier Syndrome include variable to low platelet and red blood cell counts along with abnormally large Platelets seen during a microscopic exam of a blood sample. Severe, and sometimes life threatening, bleeding can occur in response to trauma or during routine surgery of these dogs. Whelping may result in severe episodes in female dogs. Treatment is mostly supportive but may require one or more blood transfusions depending on the severity of the episode. With appropriate management, these dogs can experience a good quality of life.

Breed-Specific Information for the Cocker Spaniel

The Mutation of the GP9 gene associated with Bernard-Soulier Syndrome has been identified in the cocker spaniel. One study of 98 cocker spaniels from Europe found 7.1% to be carriers of the mutation.

Testing Tips

Genetic testing of the GP9 gene in cocker spaniels will reliably determine whether a dog is a genetic Carrier of Bernard-Soulier Syndrome. Bernard-Soulier Syndrome 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 GP9 gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms do not appear until adulthood, genetic testing should be performed before breeding. 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. Cocker spaniels 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.


  • Gentilini F, Turba ME, Giancola F, Chiocchetti R, Bernardini C, Dajbychova M, Jagannathan V, Drögemüller M, Drögemüller C. A large deletion in the GP9 gene in Cocker Spaniel dogs with Bernard-Soulier syndrome. PLoS One. 2019 Sep 4;14(9): e0220625. [PubMed: 31484196]