Common Symptoms
Hemophilia A (Rhodesian Ridgeback Type) is an inherited bleeding disorder affecting Rhodesian ridgebacks. Hemophilia A (Rhodesian Ridgeback Type) is caused by a deficiency of coagulation factor VIII, an essential protein needed for normal blood clotting. While there is some variation in bleeding tendency with this disease, Rhodesian ridgebacks may present at birth with prolonged bleeding from the umbilical cord. As affected dogs age they may also bruise easily, have frequent nosebleeds, bleed from the mouth when juvenile teeth are lost, or show signs of lameness or stiffness if bleeding occurs in the joints or muscle. There is significant risk for prolonged bleeding after surgery or trauma, where the bleeding may be severe enough to be fatal. Veterinarians performing surgery on known affected dogs should have ready access to blood banked for transfusions.
Breed-Specific Information for the Rhodesian Ridgeback
The Mutation of the F8 gene associated with Hemophilia A (Rhodesian Ridgeback Type) has been identified in the Rhodesian ridgeback, although its overall frequency in this breed is unknown.
Testing Tips
Genetic testing of the F8 gene will reliably determine whether a dog is a genetic Carrier of hemophilia A (Rhodesian Ridgeback Type). Hemophilia A (Rhodesian Ridgeback Type) is inherited in an X-Linked Recessive manner in dogs meaning that female dogs must receive two copies of the mutated gene (one from each parent) to develop the disease while male dogs only require one copy of the mutated gene from the mother in order to develop disease. Therefore, male dogs more commonly present with symptoms of the disease. Each male pup that is born to a female dog known to be a carrier of hemophilia B has a 50% chance of inheriting the disease. Reliable genetic testing is important for determining breeding practices. Because female carriers generally do not have features of the disease, 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. Rhodesian ridgebacks 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.
References
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Kehl A, Haaland AH, Langbein-Detsch I, Mueller E. A SINE Insertion in F8 Gene Leads to Severe Form of Hemophilia A in a Family of Rhodesian Ridgebacks. Genes (Basel). 2021 Jan 21;12(2):134. doi: 10.3390/genes12020134.
[PubMed: 33494213]
