Factor XI deficiency is an inherited clotting disorder affecting dogs. Factor XI is an essential protein needed for normal blood clotting. Deficiency of this factor most commonly results in a mild bleeding disorder. An affected dog may bruise easily, have frequent nosebleeds, and exhibit prolonged bleeding after surgery or trauma. In rare cases, the bleeding may be severe. Due to the mild nature of this disorder, affected dogs may not be identified until a surgery is performed or trauma occurs at which time excessive bleeding is noted. Veterinarians performing surgery on dogs that are known to have coagulation factor XI deficiency should have ready access to blood banked for transfusions. Most dogs with this condition will have a normal lifespan despite increased blood clotting times.
Genetic testing of the F11 gene will reliably determine whether a dog is a genetic Carrier of factor XI deficiency. Factor XI deficiency 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 F11 gene mutation. Reliable genetic testing is important for determining breeding practices. Because this mutation shows Variable Expressivity, 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. 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.
Knowler C, Giger U, Dodds WJ, Brooks M. Factor XI deficiency in Kerry Blue Terriers. J Am Vet Med Assoc. 1994 Dec 1;205(11):1557-61.
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