Two unrelated bleeding disorders have been identified in Deerhounds to date, both of which typically happen when a Deerhound undergoes surgery or experiences major trauma:
- Factor VII deficiency (FVIID) can affect a dog’s ability to form clots, so tends to happen during surgery. It is treated by giving the affected dog plasma from a dog without FVII deficiency.
- Delayed Post-operative Hemorrhage (DEPOH—also sometimes called Delayed Bleeding Syndrome or hyperfibrinolysis) is a disorder of clot stability, not clot formation, which is why the bleeding is usually (but not always) delayed, typically starting within 24–48 hours after surgery or major trauma. It is prevented or treated with aminocaproic acid or tranexamic acid.
- These issues are unrelated and not mutually exclusive: It is entirely possible for a Deerhound to have both Factor VII deficiency and DEPOH—that is, to be at risk of excessive bleeding both during and after surgery/injury.
- A genetic test for FVIID is widely available (here is a list of some labs that offer it), and a genetic test for DEPOH is available from Washington State University*. It is recommended that all Deerhound owners know the genetic status of their dogs for both FVIID and DEPOH so preparations can be made should a dog affected by one or both of these conditions need surgery or suffer from major injuries.
Factor VII Deficiency
Factor VII Deficiency (FVIID) occurs when a dog has no copies of the normal Factor VII gene and instead has two copies of a variant form of the gene. This condition is found in several breeds, including Deerhounds, and also mixed-breed dogs. The disease can affect dogs of either sex.
The Factor VII gene contains instructions for making a protein called Factor VII, which helps blood to clot. The Factor VII protein made by the variant form of the gene does not work as efficiently as that made by the normal form of the gene. As a result, Deerhounds with Factor VII deficiency can have trouble making effective blood clots and so are at higher risk of excessive bleeding during surgery or a major trauma (such as being hit by a car).
The Factor VII variant is inherited as an autosomal recessive gene, so a dog can be either clear (no copies of the variant), a carrier (one copy of the variant), or affected (two copies of the variant). Only an affected Deerhound has an increased risk of excessive bleeding. Dogs that are clear or carriers form blood clots normally.
Affected Deerhounds have no problems day-to-day and lead normal lives but have a higher risk of bleeding during surgery or trauma. Some FVII-affected Deerhounds have no problems during surgery, some have mild bleeding, and others bleed severely and can die. We don’t know what the increased risk of bleeding is. If they are going to bleed, dogs with Factor VII deficiency usually start to bleed during surgery.
A blood test called a Prothrombin Time (PT) can provide some information on an affected dog’s likelihood to bleed due to FVII deficiency and is good to run on affected dogs before surgery. It can also be run on dogs whose FVII status isn’t known to get a better idea of their bleeding risk.
If bleeding starts during surgery, it can be treated with plasma from a dog without Factor VII deficiency. It is important to know that not all veterinary clinics have plasma on hand; should an affected dog need surgery it is essential they go somewhere that has plasma in case a problem occurs. Breeders should discuss with their vets the potential risks should a Factor-VII-affected bitch need a c-section, and owners of affected dogs should make sure that their dogs’ records note in a prominent place that their dog is affected and a plan is in place should their dog need surgery or is severely injured.
There is a genetic test available for Factor VII Deficiency in Deerhounds, and all Deerhound owners should know the Factor VII status of their dogs. Knowing Factor VII status is included in the Health Testing Guidelines for the SDCA Code of Ethics for both puppies and adults, and responsible breeders tell puppy buyers in writing whether or not their puppy is affected based on either test results or knowledge of the parents’ Factor VII status. Many of the labs on the OFA’s list of labs run the Factor VII genetic test.
For breeders, the goal should be to never produce an affected individual. A Factor VII-clear Deerhound (no copies of the mutation) can be bred to mates of any Factor VII status. A Deerhound that is a Factor VII carrier (one copy of the mutation) or that has Factor VII deficiency (two copies of the mutation) should be bred only to a mate that is Factor VII-clear. Remember, a genetic test should not alter WHO gets bred, only WHO the dog gets BRED TO. It is only through using all of the bloodlines we have that we’ll be able to maximize the effectiveness of the tests and improve the health of our breed, so no dog or line should be eliminated from breeding because of Factor VII genetic status, especially in light of our shrinking gene pool.
The important thing is every Deerhound owner should know the Factor VII status of their dogs so proper precautions can be taken for affected dogs should surgery be needed or trauma occurs.
Here is more information on Factor VII Deficiency.
Delayed Post-operative Hemorrhage
Delayed Post-operative Hemorrhage (DEPOH), sometimes also called Delayed Bleeding Syndrome or hyperfibrinolysis, occurs when a dog has one or two copies of a variant form of a gene that is involved in preventing blood clots from dissolving until after a wound has healed. This condition is found in several breeds, including Deerhounds, and also mixed-breed dogs. The disease can affect dogs of either sex.
When a blood clot forms to stop a wound from bleeding, the clot normally is dissolved after the wound heals. A normal DEPOH gene contains instructions for making a protein that prevents blood clots from dissolving. But the protein made by the variant form of the gene does not work as efficiently as that made by the normal form of the gene. As a result, blood clots in Deerhounds with DEPOH can dissolve prematurely after major surgery or trauma. Problems, including severe skin bruising and bleeding from the wound, are typically first noticed one or two days after surgery or injury but have been seen as early as right after surgery.
The variant causing DEPOH is inherited as a dominant gene with incomplete penetrance, so dogs are either clear (no copies of the mutation) or affected (having one or two copies of the gene). Current research shows that, compared to a clear dog, a dog with one copy of the DEPOH variant is 28 times more likely to experience delayed bleeding, while a dog with two copies is 1235 times more likely to experience delayed bleeding.
Dogs that have one or two copies of the DEPOH variant have no problems day-to-day and lead normal lives, but they have a higher risk of bleeding after surgery or trauma. For reasons not yet understood, affected dogs (especially dogs with only one copy of the DEPOH variant) can undergo surgery without experiencing delayed bleeding problems. But if delayed bleeding does occur, it can be fatal, particularly if it isn’t caught soon after it starts.
Most bleeding starts within 24–48 hours after surgery, although there are cases where it starts earlier. There is no way to predict how an individual DEPOH-affected dog will react during or after major surgery. Bleeding can be prevented and/or treated with administration of aminocaproic acid (also known by its brand name, Amicar) or tranexamic acid. One of these drugs should be given prophylactically to dogs with two copies of the DEPOH variant (homozygous affected dogs) beginning the day of surgery at least three hours prior to the procedure and then three times daily for five days. For dogs with one copy of the DEPOH variant (heterozygous affected) or dogs whose genetic status is unknown, closely monitoring the dog for 48 hours after surgery/injury, having the drug on hand, and giving it if signs of hemorrhage develop will usually be effective. Owners who choose to monitor should make sure the hospital has 24-hour coverage and some aminocaproic or tranexamic acid on hand if the dog is staying overnight. Please note: most veterinary clinics do not stock either of these two medications, so owners of dogs with one or two copies of the DEPOH mutation or whose dogs’ DEPOH status isn’t known are encouraged to keep an up-to-date supply.
There may be a risk of thrombosis if given to unaffected individuals.
Dogs that have a bleeding episode post-operatively or after major trauma should be treated immediately with either aminocaproic acid or tranexamic acid, the first dose given IV slowly, if possible (if not, give the drug orally), and subsequent doses given every 8 hours orally if the dog can take meds that way. Treatment usually continues for five days.
There is now a genetic test for DEPOH available at Washington State University*. (Currently Washington State University is the only lab running the test.) Clear dogs will not need aminocaproic acid or tranexamic acid post-operatively, but dogs with one copy of the DEPOH mutation will need one of those medications on hand and given if needed, and dogs with two copies of the DEPOH mutation need to be given one of the medications the day of and for five days after surgery.
All Deerhound owners should know the DEPOH status of their dogs. Knowing DEPOH status is included in the Health Testing Guidelines for the SDCA Code of Ethics for both puppies and adults, and responsible breeders tell puppy buyers in writing whether or not their puppy is affected based on either test results or knowledge of the parents’ DEPOH status.
For breeders, the goal should be to never produce an affected individual. A DEPOH-clear Deerhound (no copies of the mutation) can be bred to mates of any DEPOH status. A Deerhound that has one or two copies of the DEPOH mutation should be bred only to a mate that is DEPOH-clear. Remember, a genetic test should not alter WHO gets bred, only WHO the dog gets BRED TO. It is only through using all of the bloodlines we have that we’ll be able to maximize the effectiveness of the tests and improve the health of our breed, so no dog or line should be eliminated from breeding because of DEPOH genetic status, especially in light of our shrinking gene pool.
A new genetic test is extremely exciting news for us, but PLEASE remember that this is a treatable and preventable problem: what this test is going to tell us is which dogs are at risk of post-operative bleeding and need treatment with aminocaproic acid or tranexamic acid. We are NOT saying that dogs should be removed from the gene pool because they have this mutation. OUR GENE POOL CANNOT AFFORD TO BE REDUCED ANY MORE. So please: although everyone’s first instinct is to remove dogs with a potentially harmful mutation from breeding programs, we need to change our thinking to just take DEPOH status into account when planning breedings and to inform puppy buyers of their puppy’s DEPOH status—just like Factor VII.
The important thing is every Deerhound owner should know the DEPOH status of their dogs so proper precautions can be taken for affected dogs should surgery be needed or trauma occurs.
Here is Dr. Court’s presentation at the 2021 National Specialty.
Read this article on how these two variants were discovered in Deerhounds.
* As part of the patent agreement between WSU and the SDCA, a small royalty from DEPOHGEN™ test sales will be returned to the SDCA.