Von Willebrand Disease: The Canine Bleeding Disorder
Von Willebrand disease (vWD) is the most common inherited bleeding disorder in dogs, affecting numerous breeds with varying degrees of severity. Unlike hemophilia, which affects only males, vWD affects both sexes equally because the von Willebrand factor gene is located on an autosome (chromosome 27 in dogs), not a sex chromosome. For herding breed breeders, vWD is particularly relevant because several herding and herding-adjacent breeds carry significant allele frequencies for disease-causing variants.
The condition is named after Erik von Willebrand, who first described it in humans in the 1920s. Von Willebrand factor (vWF) is a large glycoprotein produced by endothelial cells and megakaryocytes (platelet precursor cells). It plays two critical roles in hemostasis: facilitating platelet adhesion at sites of vascular injury and carrying and protecting coagulation factor VIII in circulation. When vWF is absent or functionally deficient, the normal clotting cascade is disrupted, leading to prolonged bleeding from wounds, surgical sites, or spontaneously from mucous membranes.
The Three Types and Their Genetic Mechanisms
Canine vWD is categorized into three types based on the quantity and functional characteristics of the vWF present:
Type 1 vWD
Type 1 is the mildest and most common form, characterized by a partial quantitative deficiency of vWF. Dogs with Type 1 have reduced but functional vWF and may show mild to moderate bleeding tendencies. The condition is inherited in an autosomal dominant manner with incomplete penetrance, meaning that a single copy of the variant allele is sufficient to reduce vWF levels, but the degree of reduction and clinical expression varies among individuals.
Doberman Pinschers are the classic Type 1 breed, where carrier frequencies are extraordinarily high — studies have documented that 70% or more of Dobermans in some populations are carriers or affected. While Dobermans are not herding dogs, they illustrate the scale of the challenge when a disease allele becomes highly prevalent in a closed population.
Type 2 vWD
Type 2 involves a qualitative defect: vWF is present in approximately normal quantities but is structurally abnormal, lacking the high-molecular-weight multimers that are most effective at supporting platelet adhesion. The bleeding severity in Type 2 is disproportionate to the vWF quantity measured by standard assays, making diagnosis more complex.
German Wirehaired Pointers and German Shorthaired Pointers are the primary breeds affected by Type 2 vWD. These pointing breeds are not herding dogs, but they share registries and sometimes breeding populations with versatile working dogs that breeders may consider crossing with herding breeds.
Type 3 vWD
Type 3 is the most severe form, involving a near-complete or complete absence of vWF. Affected dogs have no functional vWF at all and suffer from severe bleeding that can be life-threatening. Spontaneous hemorrhage into joints, muscles, and body cavities can occur. Affected individuals typically require blood product transfusions for surgical procedures and may have significantly shortened lifespans due to hemorrhagic complications.
Type 3 is inherited as an autosomal recessive: only dogs homozygous for the causative variant are severely affected, while heterozygous carriers have sufficient vWF for normal hemostasis in most circumstances. The breeds most significantly affected by Type 3 include Scottish Terriers, Chesapeake Bay Retrievers, and Shetland Sheepdogs. The Sheltie connection makes Type 3 vWD directly relevant to herding breed breeders.
Von Willebrand Disease in Herding Breeds
Shetland Sheepdogs (Shelties)
Shelties carry a distinct Type 3 vWD variant that has been identified and sequenced. This is an autosomal recessive condition: carrier Shelties are normal, but when two carriers are paired, 25% of their offspring can be severely affected. Given the breed’s popularity and the fact that the vWD allele was likely present in founding individuals, the carrier frequency in some Sheltie populations has historically been meaningful enough to warrant routine testing of all breeding animals.
German Shepherds
German Shepherds have been documented with von Willebrand disease, though the condition is less prevalent than in some other breeds. The inheritance pattern in German Shepherds is complex and has not been as thoroughly characterized as in Shelties or Dobermans. Some German Shepherd vWD cases appear to be Type 1, while others may represent separate mutations. Breeders should be aware that bleeding tendencies in a German Shepherd warrant evaluation, though vWD is not the most common bleeding concern in the breed overall.
Collies and Related Breeds
Rough and Smooth Collies have been reported to carry vWD, though systematic prevalence data across collie populations is more limited than for Shelties. Given the close relationship between these breeds and the shared founder ancestry that shapes so many herding breed health challenges — including the genetic bottlenecks that affect population diversity — awareness of vWD risk is warranted for breeders across the collie family.
Clinical Signs and Presentation
The clinical presentation of vWD depends on the type and severity:
In Type 1 and mild Type 3 carriers, the condition may go undetected until the dog undergoes surgery or suffers significant trauma. Prolonged bleeding from puppy tooth loss, prolonged clotting after minor cuts, or unusual bleeding during routine surgeries may be the first clues. Some Type 1 dogs bleed significantly during spay or neuter surgery, which is often when the condition is first identified.
In Type 3 affected dogs, spontaneous bleeding from the nose (epistaxis), gums, or urinary tract may be seen even without trauma. Lameness due to joint hemorrhage can mimic orthopedic problems. Subcutaneous hematomas may develop without identifiable injury. These dogs represent a genuine veterinary emergency when bleeding episodes occur, and owners must be prepared to seek immediate blood transfusion support.
Stress and estrogen fluctuations associated with estrus can transiently worsen vWD symptoms in females, sometimes making the first breeding cycle the point at which a previously unrecognized mild case becomes apparent.
Diagnosis: From Clinical to Molecular
Classic vWF Assay
The traditional diagnostic approach measures vWF antigen levels in blood plasma as a percentage of normal. Healthy dogs typically have vWF antigen levels between 70% and 200% of the reference range. Values below 50% suggest Type 1 or early Type 3, while values below 1% are consistent with Type 3. However, vWF levels fluctuate with stress, exercise, thyroid status, and inflammatory states, reducing the reliability of a single-point measurement.
Multimer Analysis
For suspected Type 2 vWD, analysis of vWF multimers (the molecular weight distribution of vWF complexes) in plasma is required to identify the qualitative abnormality. This is a specialized test not available at all veterinary diagnostic laboratories.
DNA Testing
For breeds where the specific causative mutation has been identified, DNA testing offers definitive carrier detection. Unlike vWF antigen assays, DNA tests are not affected by the dog’s physiological state on the day of testing, do not require the dog to be fasted, and distinguish carriers from clear dogs with certainty. As with other recessive conditions, this is the testing approach advocated for breeding programs. Our guide to canine DNA testing discusses how to choose appropriate laboratories and integrate results into breeding decisions.
The limitation of DNA testing for vWD is that it only detects the specific mutation or mutations included in the panel. In breeds where the causative mutation has not been fully characterized, or where multiple mutations may cause the same phenotype, a DNA “clear” result does not guarantee freedom from all possible forms of vWD.
Breeding Strategies
For Type 3 vWD in Shelties, the carrier × clear strategy applies directly:
- Clear × clear: All offspring clear. Ideal.
- Carrier × clear: 50% clears, 50% carriers. Produces no affected puppies.
- Carrier × carrier: 25% affected, 50% carriers, 25% clear. Avoid.
- Affected × any: Produces carriers at minimum. Not recommended.
The same considerations about genetic diversity that apply to other recessive conditions govern the management of vWD carriers. Culling all carriers from a Sheltie breeding program in a single generation would be biologically inadvisable if it substantially reduced the effective population size or concentrated other recessive alleles. The goal is systematic reduction of the disease allele frequency across generations, not immediate elimination at the cost of genetic narrowing.
For Type 1 vWD in German Shepherds, where the inheritance is less clearly recessive and penetrance is variable, breeding guidance requires individual assessment based on measured vWF levels, clinical history, and the degree to which the dog’s other qualities justify its inclusion in a program.
Living With an Affected Dog
Owners of vWD-affected dogs can successfully manage the condition with preparation. Key measures include:
Surgical planning: All elective procedures should be delayed until a veterinary team familiar with vWD management can be engaged. Blood products including fresh frozen plasma or cryoprecipitate (which concentrates vWF) should be available for transfusion before any anesthesia.
Wound management: Minor cuts that would normally be trivial may require direct pressure for extended periods. Owners should be trained in basic wound care and know when to seek emergency veterinary assistance.
Medication awareness: Several commonly used drugs impair platelet function and should be avoided or used with extreme caution in vWD-affected dogs. These include aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and certain anesthetic agents. This medication awareness parallels the drug sensitivity considerations described in our MDR1 gene guide, where herding breed dogs require special attention to drug interactions.
Monitoring for bleeding signs: Regular monitoring of the gums, nose, and stool for signs of bleeding allows early detection of complications. Owners should have a relationship with a veterinary emergency service that can provide transfusion support promptly if needed.
The Future of vWD Management
Advances in gene therapy and molecular medicine hold potential for eventually treating rather than just managing vWD in affected dogs. Proof-of-concept studies have demonstrated that viral vector delivery of a functional VWF gene can restore hemostasis in animal models of the disease. While clinical availability is likely still some years away, the pace of progress in canine genomic medicine, reviewed in our article on future developments in this field, gives grounds for cautious optimism.
For the present, the combination of comprehensive DNA testing, responsible breeding practices, and careful veterinary management represents the most effective strategy. Routine testing of all Sheltie breeding stock, along with awareness across the broader herding dog community, can progressively reduce the impact of this preventable disease on the population.