Clinical perspective: Bleeding disorders

Many different types of hereditary bleeding disorders have been encountered in dogs, some of which are quite common in certain breeds (Table 1). Most of these cause spontaneously only mild bleeding, such as nosebleeds or bleeding of the gums. However, many bleeding disorders can cause excessive, even life-threatening, bleeding after surgery or trauma.

Table 1. The occurrence of certain common bleeding disorders in certain breeds

Breed Disorder Clear Carrier Affected
Greater Swiss Mountain Dog Bleeding Disorder Due To P2RY12 Defect 39 % 48 % 13 %
Beagle Factor VII Deficiency 54 % 41 % 5 %
Deerhound Factor VII Deficiency 55 % 44 % 2 %
Finnish Hound Factor VII Deficiency 73 % 26 % 1 %
Welsh Springer Spaniel Factor VII Deficiency 72 % 26 % 2 %
Shih Tzu Prekallikrein Deficiency 79 % 20 % 1 %

Mild spontaneous signs – severe bleeding after surgery or trauma

Because of only mild or inapparent spontaneous clinical signs, hereditary bleeding tendency is often diagnosed after, during or before surgery. Some hereditary bleeding disorders cause alterations in clotting times that can be seen if a screening panel is done before surgery. Some bleeding disorders do not cause any alterations in clotting times and the bleeding tendency is noticed only when the animal has already undergone surgery and is already bleeding excessively.

In surgical patients with a known bleeding disorder, surgical interventions and dental procedures can be planned to be as safe as possible. Extra caution can be taken to stop even minor bleeding. In certain bleeding disorders, certain medications can be administered preoperatively to normalize clotting and increase surgical safety. In patients that have a severe bleeding disorder like for example Hemophilia A, the need for surgery can be weighed in a cost-benefit –manner. Genetic testing of these disorders would be advisable before surgery in breeds that are susceptible to bleeding disorders.

This dog is bleeding – why?

When a patient with spontaneous bleeding comes in, after initial stabilization, it is crucial to investigate the cause of bleeding. Hereditary bleeding disorders can be suspected when other possible causes for bleeding have been ruled out and by combining the results of blood clotting tests. Hereditary clotting disorders can be difficult to fully diagnose in an emergency situation because of the lack of on-side diagnostic tests. Knowing the dog’s hereditary bleeding tendency beforehand would save time and guide treatment to the right direction right away.

Supposedly breed-specific mutations have been found in other breeds

Some mutations originally published as breed-specific appear to be widespread and common also in other breeds. One of these mutations is the one causing Von Willebrand’s Disease Type 2. Genoscoper is performing clinical studies where it is studied, whether these mutations cause disease in other breeds than published before. If your dog has a bleeding tendency of unknown origin, please feel free to contact our scientist Heidi Anderson: heidi.anderson@genoscoper.com. Table 2 lists the breeds that we are most interested in. In these breeds we have found genetic variants that cause bleeding disorders in other breeds.

Table 2. New breeds with genetic variants potentially causing bleeding disorders

Barbet Miniature Schnauzer
Basenji Norwegian Elkhound
Border Collie Old English Sheepdog
Chinese Crested Dog Papillon
Danish-Swedish Farmdog Phalene
Dutch Shepherd Dog Pointers
German Spitz Poodles
Irish Water Spaniel Portuguese Water Dog
Japanese Spitz Russo-European Laika
Kromfohrländer Sealyham Terrier
Lagotto Romagnolo Toy Fox Terrier

Which bleeding disorders can be tested?

MyDogDNA includes tests for mutations causing the following bleeding disorders: Von Willebrand’s Disease types 1, 2 & 3, Haemophilia A & B, Bleeding Disorder Due To P2RY12 Defect, Factor VII Deficiency, Factor XI Deficiency, Prekallikrein Deficiency, Pyruvate Kinase Deficiency, May-Hegglin Anomaly, Glanzmann Thrombastenia, Thrombopathia and Canine Scott Syndrome. Many different breeds are affected by these disorders. Check the Breeds-page to learn more about the diseases in your breed.

Always inform your veterinarian if your dog has been diagnosed with a bleeding disorder.