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P2RY12-associated Bleeding Disorder

This is a bleeding disorder due to a blood protein (P2RY12) defect and was first described in Greater Swiss Mountain Dogs.

Found in

1 in 2,500 dogs

in our testing

Key Signs

Excessive and prolonged bleeding after trauma or surgery, Spontaneous bleeding is unlikely

Age of Onset

At birth

Present at birth


Autosomal Recessive

For autosomal recessive disorders, dogs with two copies of the variant are at risk of developing the condition. Dogs with one copy of the variant are considered carriers and are usually not at risk of developing the disorder. However, carriers of some complex variants grouped in this category may be associated with a low risk of developing the disorder. Individuals with one or two copies may pass the disorder-associated variant to their puppies if bred.

Likelihood of the Condition

Moderate-high likelihood

At risk dogs are likely to show signs of this disease in their lifetime.

What to Do

Here’s how to care for a dog with P2RY12 bleeding defect

Partner with your veterinarian to make a plan regarding your dog’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.

For Veterinarians

Here’s what a vet needs to know about P2RY12 bleeding defect

This disorder may lead to excessive bleeding in the event of surgery or trauma. The excessive bleeding is caused by a failure of blood platelet aggregation, and may potentially be fatal. Spontaneous bleeding is usually not encountered in affected dogs.

Affected dogs should be monitored closely for excessive and prolonged bleeding during and after any required surgical procedures or after any trauma. Blood or platelet transfusions should be provided as necessary to ensure proper clotting if other means are unsuccessful.

For Breeders

Planning to breed a dog with this genetic variant?

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to be shown. A carrier dog with one copy of the P2RY12 bleeding defect mutation can be safely bred with a clear dog with no copies of the P2RY12 bleeding defect mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the P2RY12 bleeding defect mutation. A dog with two copies of the P2RY12 bleeding defect mutation can be safely bred with a clear dog. The resulting puppies will all be carriers. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disease signs similar to the ones caused by the P2RY12 bleeding defect mutation could develop due to a different genetic or clinical cause.

Technical Details

Gene P2RY12
Variant Deletion
Chromosome 23
Coordinate Start 45,909,989
Coordinate End 45,909,987

All coordinates reference CanFam3.1

References & Credit

Credit to our scientific colleagues:

Boudreaux, M. K., & Martin, M. (2011). P2Y12 receptor gene mutation associated with postoperative hemorrhage in a Greater Swiss Mountain dog. Veterinary Clinical Pathology, 40(2), 202–206. View the article