Thrombopathia is an autosomal recessive blood disorder that occurs in Landseer Newfoundlands. Thrombopathia is characterized by excessive bleeding due to lack of platelet function. Dogs with thrombopathia can lead relatively normal lives but are at increased risk of hemorrhage during accidental injury or during surgery.
Thrombopathia is caused by the failure of normal platelet clotting. Normally, platelets stick together in order to prevent blood loss until the wound is repaired. Due to a mutation in the RasGRP gene, platelets are unable to function normally. This gene regulates systemic vascular resistance, meaning that interruptions in the genetic code can impact blood clotting and platelet formation.
Dogs with thrombopathia experience frequent and/or spontaneous bleeding and are at risk for spontaneous or excessive hemorrhage. Bleeding can be typically noticed in the gums, especially after chewing on hard objects or when new adult teeth are growing in. Dogs with thrombopathia are prone to nosebleeds. Dogs bruise easily and are prone to internal bleeding, which can sometimes be noticed in bloody or tarry stool. Bleeding can occur in the gastrointestinal tract and the urinary tract. Bleeding in the joints can cause the dog to be stiff or lame. Thrombopathia may not be noticed until a surgery or trauma occurs, at which point excessive bleeding is noted. During surgery, veterinarians must have blood ready for transfusions when operating on a dog that is known to have thrombopathia.
Thrombopathia is an autosomal recessive disorder. This means that a dog must inherit two copies of the mutation in order to present symptoms of thrombopathia. A dog with one copy of the mutation is known as a carrier and does not present symptoms. If two carriers are bred to one another, there is a 25% chance per puppy born that they will develop symptoms of thrombopathia and a 50% chance per puppy born that they will also be carriers of thrombopathia. Because thrombopathia is not treatable, the best way to manage thrombopathia is through prevention. Genetic testing can reveal the likelihood of a dog developing thrombopathia and can inform a breeder of major health concerns.
|T/T||Affected: Dog has two copies of the Thrombopathia mutation and is at risk of being affected by the disorder. The mutation will always be passed on to every offspring.|
|T/n||Carrier: Dog carries one copy of the mutation associated with Thrombopathia.|
|n/n||Clear: Dog is negative for the mutation associated with Thrombopathia.|
Boudreaux MK, Catalfamo JL, Klok M. Calcium-diacylglycerol guanine nucleotide exchange factor I gene mutations associated with loss of function in canine platelets. Transl Res. 2007 Aug; 150(2):81-92. [PubMed: 17656327]