Hemophilia A (boxer type) is an inherited bleeding disorder affecting dogs. Hemophilia A (boxer type) is caused by a deficiency of coagulation factor VIII, which is an essential protein needed for normal blood clotting. Affected dogs may bruise easily, have frequent nosebleeds, bleed from the mouth when juvenile teeth are lost, and experience prolonged bleeding after surgery or trauma. Dogs may show signs of lameness or stiffness if bleeding occurs in the joints or muscle. Less often, the bleeding may be severe enough to cause death. Due to the variable severity of the 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 known affected dogs should have ready access to blood banked for transfusions.