Hemophilia A (Boxer Type)
Affected Genes: F8
Inheritance: X-Linked Recessive
Variant(canFam6):
chrX:107974558: G>C
Breed: Boxer
General Information: Hemophilia A (Boxer Type) is a genetic bleeding disorder resulting from a deficiency in coagulation factor VIII, an essential protein for normal blood clotting. Dogs affected by this condition may bruise easily, experience frequent nosebleeds, bleed from the mouth when losing juvenile teeth, and suffer prolonged bleeding after surgery or trauma. They may also show signs of lameness or stiffness if bleeding occurs in the joints or muscles. In severe cases, the bleeding can be life-threatening. Due to the variable severity of the disorder, some affected dogs may not be identified until they undergo surgery or experience trauma, revealing excessive bleeding. Veterinarians performing surgery on known affected dogs should have access to banked blood for transfusions to manage this risk effectively. Despite the increased blood clotting times, most dogs with Hemophilia A can have a normal lifespan with proper management.
How to Read Your Dog's Test Results for this Genetic Variant:
Two Variants Detected: Dog Likely Affected
One Variant Detected: Dog Unlikely Affected
No Variants Detected: No Effect
Gene / Testing Information: Genetic testing for Hemophilia A (Boxer Type) involves screening for mutations in the F8 gene to determine carrier status. This disorder is inherited in an X-linked recessive manner, meaning that female dogs must inherit two copies of the mutated gene (one from each parent) to develop the disease, while male dogs only need one copy from their mother to be affected. Consequently, male dogs are more commonly symptomatic. Each male pup born to a carrier female has a 50% chance of inheriting the disease. Genetic testing is crucial for responsible breeding practices, as symptoms may be mild in affected dogs, and female carriers typically do not show symptoms. To avoid producing affected puppies and eliminate the mutation from breeding lines, it is essential not to breed two known carriers. Dogs that are not carriers of the mutation do not pose a risk of producing affected offspring.
References:
Christopherson PW, Bacek LM, King KB, Boudreaux MK. Two novel missense mutations associated with hemophilia A in a family of Boxers, and a German Shepherd dog. Vet Clin Pathol. 2014 43(3):312-316.