TNS (Trapped Neutrophil Syndrome) in Border Collies

Trapped Neutrophil Syndrome (TNS) represents a frequently lethal autosomal genetic disorder exclusively identified in Border Collies. The term “trapped” in TNS refers to the confinement of neutrophils within the marrow. This condition results in the bone marrow generating neutrophils as usual, yet these crucial immune cells fail to migrate into the bloodstream, which is essential for combating infections.

Unfortunately, the compromised immune system associated with this syndrome often leads to a grim prognosis and affected puppies typically struggle to survive beyond their initial year of life. The specificity of TNS to Border Collies underscores its genetic nature, highlighting the importance of genetic screening and responsible breeding practices within this canine population.

What is Trapped Neutrophil Syndrome?

Puppies with TNS typically experience chronic diseases due to a weakened immune system, exhibiting smaller size, developmental delays, and distinctive features such as a narrow, elongated skull and slender extremities.

The onset of infections can occur as early as six weeks, with some dogs showing mild clinical signs only emerging at two years or older. This genetic autosomal disorder poses a significant health risk, potentially leading to a compromised quality of life for affected dogs. Early detection and management are crucial for improving outcomes in these cases.

Disease Information

Trapped Neutrophil Syndrome was first identified in 1996 in New Zealand and Australia, with pioneering research from Australia. This debilitating condition has solely emerged in Border Collies within the past eight years, presenting a significant challenge as there are presently no known cures or treatments for affected puppies and dogs.

Typically manifesting in young puppies before they join their permanent homes, TNS may sometimes remain undetected until the pups reach up to 7 months of age.

Genetics of the Disease

the impact of genetics in the disease

Trapped Neutrophil Syndrome (TNS) follows a recessive inheritance pattern, requiring both parent dogs to pass on a VPS13B gene mutation for the disease to manifest. Dogs inheriting just one mutated gene are carriers, not displaying any symptoms. However, if bred with another carrying the same mutation, these carriers could produce affected puppies. Yet, pairing carriers with dogs lacking the mutation won’t yield affected offspring.

This inheritance complexity poses a challenge in breeding, as carriers’ potential to transmit the mutation necessitates cautious pairing to prevent the birth of affected puppies. Thus, responsible breeding practices involve genetic testing to avoid unintentionally passing on TNS, ensuring the well-being of future generations of Border Collies.


The dog does not carry the mutated gene responsible for Trapped Neutrophil Syndrome (TNS), significantly reducing the risk of developing this condition. As a non-carrier, it won’t pass on the mutation to its offspring, making it a suitable candidate for breeding with any other dog without the concern of transmitting the syndrome.

This absence of the mutated gene ensures that future generations from this dog won’t inherit TNS, allowing for a broader choice in breeding partners while safeguarding against the spread of this genetic disorder.


Canines carrying two copies of the mutated gene suffer from the condition when two dogs with one copy of the gene each mate. The resulting litter is anticipated to have 25% healthy offspring, 50% carriers, and 25% inheriting the mutant allele from both parents, likely developing Trapped Neutrophil Syndrome (TNS).

This genetic pattern underscores the recessive nature of the disorder, where two copies of the faulty gene are necessary to manifest the condition. This inheritance model commonly occurs in various genetic diseases, where carriers, though not affected, can pass on the gene to their offspring, potentially leading to the manifestation of the disorder if both parents contribute the mutated gene.


When a dog possesses two copies of the mutant gene associated with Trapped Neutrophil Syndrome (TNS), it will transmit this genetic anomaly to all its offspring. This hereditary condition significantly increases the likelihood that the dog will develop TNS.

Trapped Neutrophil Syndrome is a potentially severe disorder characterized by the entrapment of neutrophils, essential immune cells, impairing the individual’s ability to combat infections. Consequently, the dog not only faces the risk of suffering from TNS but also becomes a genetic carrier, perpetuating the transmission of the mutant gene to subsequent generations.

Symptoms of TNS in Border Collies

Several Border Collie puppies affected by Trapped Neutrophil Syndrome (TNS) exhibit distinctive characteristics, resembling a ‘ferret-like’ head structure, diminished size compared to their counterparts, and unusually sluggish growth rates. Additionally, a common manifestation is poor hair growth on their coats. While some puppies initially appear normal, they display symptoms once they fall ill.

These symptoms encompass lameness, diarrhea, fever, and a specific reaction to vaccinations marked by an elevated temperature. The affected puppies also exhibit a loss of appetite and poor overall growth. These varied indicators underscore the complexity and severity of TNS, emphasizing the need for awareness and proactive veterinary care in managing this genetic disorder in Border Collies.

Trapped Neutrophil Syndrome Causes in Border Collies

Border Collies have been discovered to carry trapped neutrophil syndrome that is mainly brought by a reduction in white blood cells, specifically neutropenia. This condition stems from a Vesicle Protein Sorting 13B (VPS13B) gene mutation. TNS hampers the immune system’s ability to function effectively due to the affected gene, causing a scarcity of neutrophils to fight infections.

This genetic mutation affects the average production and release of these vital immune cells, leaving affected dogs vulnerable to recurrent infections and other health complications. Identifying the VPS13B gene mutation has shed light on the underlying cause of this neutropenia observed in Border Collies.

How to Diagnose Trapped Neutrophil Syndrome in Border Collies?

Animals affected by this condition are diagnosed through blood tests that reveal a low count of neutrophils, while bone marrow biopsies show abundant of these cells. This discrepancy between blood tests and bone marrow analysis is a significant indicator for diagnosing the condition.

It helps veterinarians differentiate between trapped neutrophils within the bone marrow and the lack of these crucial immune cells in the bloodstream. This diagnostic method enables a more accurate understanding of the ailment’s mechanism, allowing for targeted treatments and care plans to support the affected animal’s immune system and overall health.

Treatment of Trapped Neutrophil Syndrome in Border Collies

While there isn’t a cure for TNS, the condition is typically fatal, although, in certain instances, dogs with milder forms can receive medication and therapy. These treatments aim to extend their lifespan and improve their overall well-being. These interventions don’t eradicate the syndrome but can offer some relief and potentially enhance the affected dog’s quality of life.

The management often involves a combination of medications and supportive care tailored to the individual dog’s needs. Regular vet check-ups and close monitoring are crucial to promptly address any changes in the dog’s condition and adjust the treatment plan accordingly.


After administering a combination of prednisolone and antibiotics, a notable clinical improvement was observed, ensuring the survival of all dogs into adulthood. The short- to medium-term outcome for these treated canines were favorable. The intervention, using prednisolone for its anti-inflammatory properties and antibiotics to address underlying infections, proved effective in managing the condition.

This positive response shows the importance of timely and appropriate medical intervention in enhancing the overall health and well-being of the affected dogs. The successful treatment alleviated immediate symptoms and contributed to the short-to-medium-term survival and improved quality of life for the canine subjects.


Specific experimental treatments aim to alleviate pain, with some veterinarians advocating for antioxidant-rich diets to manage the condition. Additional recommendations include vitamin supplements and vegetarian diets, although these approaches still need to be verified and fall within the realm of experimental options. There’s ongoing exploration within veterinary medicine to discover effective remedies for the condition, but as of now, their efficacy needs to be more substantial evidence.

These potential solutions highlight the evolving nature of veterinary care for such conditions, emphasizing the need for further research and clinical validation to establish their reliability and safety in managing the ailment.

How to Prevent TNS and its Development in Border Collies?

If your dog carries the gene, it’s advised not to breed it. Pairing it with another dog could result in around 50% of their offspring being affected or becoming carriers. Breeding two carriers leads to a litter that inherits the condition.
If your dog is clear of the gene, it’s crucial to ensure any breeding partner also lacks the gene to prevent passing on the trait. Responsible breeding practices involve checking the genetic status of both parents to avoid perpetuating inherited disorders, ensuring a healthier lineage for future generations of pups.

Recovery of Trapped Neutrophil Syndrome in Border Collies

Regrettably, this condition typically proves fatal within the initial year of a dog’s life. To alleviate your pet’s potential suffering caused by recurrent infections and pain, the most compassionate option might be to consider euthanasia. This choice aims to prevent prolonged discomfort and provide a more humane end for the dog.

Consulting with a veterinarian to assess the severity of the condition and the dog’s quality of life can offer guidance and support in making this difficult decision.

What Dog Breeds are at Higher Risk of Developing Trapped Neutrophil Syndrome (TNS)?

Trapped Neutrophil Syndrome (TNS) stems from a specific mutation in the VPS13B gene, exclusive to the Border Collie breed. This hereditary ailment poses a diagnostic challenge, remaining untreatable and ultimately fatal. Initially perceived as rare, it’s now recognized as prevalent within the breed. The gene responsible for this condition is estimated to exist in approximately 10% of Border Collies globally.

Its prevalence highlights the urgency of genetic screenings within breeding programs to curb the transmission of this mutation and prevent its dire consequences. Identifying affected dogs or carriers becomes crucial to safeguard the breed’s health and minimize the occurrence of this debilitating syndrome.

What Vet Specialist to Visit if My Border Collie is Suspected to have TNS?

If you suspect your Border Collie puppy is affected by Trapped Neutrophil Syndrome (TNS), you must consult your regular veterinarian promptly. Provide them with detailed information about your observations and concerns. The veterinarian will conduct a thorough examination of your puppy, assessing for any additional health issues that could be contributing to the symptoms.

If it is a suspected TNS, your vet will arrange for DNA testing to diagnose the condition as soon as possible. Early detection is vital in managing TNS, and accurate diagnosis through DNA testing enables appropriate care and decision-making for the well-being of your puppy. Regular veterinary consultations and proactive measures are essential in addressing potential health challenges in your Border Collie.

DNA Testing for Trapped Neutrophil Syndrome (TNS) in Border Collies

DNA testing is a proactive approach which is proven to be a valuable tool in managing and mitigating the impact of TNS within the breeding community.

Trapped neutrophil syndrome (TNS) is an inheritable condition that DNA testing can accurately diagnose. This method ensures precise differentiation between affected animals, carriers, and healthy dogs.

The testing process is highly accurate and enables identification at any stage of a dog’s life. This genetic screening is crucial for identifying carriers and preventing the transmission of the mutant gene to future generations.

The ability to distinguish between affected and unaffected canines help in making informed breeding decisions, reducing the risk of passing on the syndrome.

Where is the DNA Testing Carried out?

The exclusive testing facility for Trapped Neutrophil Syndrome (TNS) is in Australia at A/Prof Peter Williamson’s laboratory in New South Wales. Dog owners worldwide can submit samples for testing, with the preferred specimen being blood collected in EDTA form. This specific anticoagulant prevents clotting on the FTA card, ensuring sample integrity. It’s crucial to utilize a minimal amount of blood and dispatch the sample directly to the Peter Williamson laboratory.

This streamlined process facilitates global accessibility for testing and aids in identifying the presence of TNS through precise genetic analysis, contributing to effective diagnosis and informed breeding decisions.

Is Trapped Neutrophil Syndrome (TNS) Curable in Border Collies?

Border Collie with TNS

Trapped neutrophil syndrome (TNS) lacks a cure and typically progresses to a fatal outcome. However, specific treatments involving antibiotics and steroids have shown efficacy in improving the quality of life for affected dogs, enabling them to engage in relatively normal activities. These treatments manage symptoms and infections associated with the condition, potentially extending the affected dog’s lifespan while enhancing overall well-being.

Despite these interventions, the syndrome remains incurable, emphasizing the importance of early detection, prompt veterinary care, and ongoing management to mitigate the severity of symptoms and sustain the dog’s comfort and activity levels.

Border Collies Tested for Trapped Neutrophil Syndrome (TNS)?

When considering the purchase of a Border Collie puppy, it is crucial to ensure that the puppy’s parents have undergone essential health screenings. This precautionary measure significantly diminishes the risk of your puppy being afflicted by specific health conditions. Health screenings are vital in identifying potential genetic disorders or hereditary conditions like TNS that may be present in the lineage of the puppy’s parents.

By choosing responsibly bred puppies from parents with a clean bill of health, you promote the overall well-being of the canine population. This approach promotes a healthier and happier life for your future furry companion, mitigating the likelihood of hereditary health issues.


Border Collie trapped neutrophil syndrome (TNS) is a rare genetic disorder that affects the immune system of Border Collies, leading to a compromised ability to fight infections. It’s caused by a mutation that disrupts the normal function of neutrophils, a type of white blood cell crucial for combating bacteria and other pathogens. Unfortunately, there’s currently no cure for TNS, and affected dogs often succumb to severe infections at a young age. Research efforts aim to understand this syndrome better, potentially leading to improved diagnostics and treatment strategies in the future. Early detection through genetic testing and responsible breeding practices are crucial steps in reducing the prevalence of this devastating condition within the Border Collie population.

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