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Trapped Neutrophil Syndrome, TNS (Failure to Thrive in Collies) in Dogs

Occurrence: very rare
Location of illness: General/Whole body

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Trapped Neutrophil SyndromeA syndrome is a group of symptoms that occur together and indicate a specific disease or condition. A syndrome can be caused by various factors and is often complex in its diagnosis and treatment. (TNS) is a genetically determined disease that occurs particularly in Collies and impairs their ability to effectively produce and release white blood cells, especially neutrophilsNeutrophils are a type of white blood cell that plays a vital role in the immune response, especially in fighting bacterial infections. They are part of the body's first line of defense against pathogens., leading to a weakened immune responseAn immune response is the immune system's reaction to foreign substances (antigens), such as microorganisms or proteins. It involves a series of processes aimed at recognizing, fighting, and eliminating these antigens..

The most important facts at a glance

Trapped Neutrophil Syndrome (TNS) is a genetic disease in Collies caused by a mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. in the GFI1 gene. This mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. prevents neutrophil granulocytes, a type of white blood cell, from leaving the bone marrow and entering the bloodstream, leading to immunodeficiency. TNS is inherited in an autosomal recessive manner, meaning that affected dogs need two copies of the mutated gene to show symptoms. Common symptoms include DiarrheaDiarrhea refers to the condition of frequent, watery bowel movements, which can be a sign of infections, digestive disorders, or other health problems., conjunctivitis, and Skin infections, while rare symptoms may include Cough or Joint pain. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made by a blood count and can be confirmed by a genetic test. There is no specific cure, so treatment focuses on symptom relief and infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring.. Antibiotics and supportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. care are crucial, but the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. often remains unfavorable as the life expectancy of affected dogs is greatly reduced. Preventive measures include genetic testing in breeding dogs to prevent the transmission of the defective gene. Research focuses on improving diagnostics and developing potential genetic correction methods. Scientists are also investigating the role of environmental factors and working on international breeding protocols. The goal is to better understand the disease and enable affected dogs to live longer, healthier lives.

Causes

Trapped Neutrophil Syndrome is based on a genetic defectA genetic defect is an abnormality or mutation in the DNA sequence of a gene that can lead to a malfunction or absence of a protein. Genetic defects can cause various genetic diseases and conditions. that impairs the maturation and release of neutrophilsNeutrophils are a type of white blood cell that plays a vital role in the immune response, especially in fighting bacterial infections. They are part of the body's first line of defense against pathogens. from the bone marrow into the bloodstream. NeutrophilsNeutrophils are a type of white blood cell that plays a vital role in the immune response, especially in fighting bacterial infections. They are part of the body's first line of defense against pathogens. are a type of white blood cell that plays a crucial role in fighting infections. In TNS, these cells remain “trapped” in the bone marrow, resulting in a reduced number in the blood.

The genetic defectA genetic defect is an abnormality or mutation in the DNA sequence of a gene that can lead to a malfunction or absence of a protein. Genetic defects can cause various genetic diseases and conditions. in TNS is inherited in an autosomal recessive manner, meaning that an affected dog must inherit two copies of the mutated gene, one from each parent, to show symptoms of the disease. Dogs that carry only one copy of the mutated gene are carriers and do not show symptoms, but can pass the disease on to their offspring.

The causative genetic mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. in TNS affects the GFI1 gene, which plays an important role in regulating genes required for normal neutrophil maturation. Abnormal function of this gene causes the neutrophilsNeutrophils are a type of white blood cell that plays a vital role in the immune response, especially in fighting bacterial infections. They are part of the body's first line of defense against pathogens. to be retained in the bone marrow instead of entering the bloodstream where they could fight infections.

Symptoms

Very common symptoms:

Common symptoms:

The symptoms of TNS usually occur in young Collies, often as early as puppyhood. Affected dogs often show signs of Failure to thrive, including growth retardation and weight loss. They may also show signs of immunodeficiency, such as recurrent infections of the respiratory tractThe respiratory tract includes the organs and structures involved in the breathing process, including the nose, pharynx, larynx, trachea, bronchi, and lungs., skin, or digestive tract.

Other common symptoms include Fever, lethargy, and general weakness. Due to the insufficient number of functioning neutrophilsNeutrophils are a type of white blood cell that plays a vital role in the immune response, especially in fighting bacterial infections. They are part of the body’s first line of defense against pathogens. in the blood, affected dogs are susceptible to bacterial infections that can be severe and sometimes life-threatening.

In some cases, enlargement of the lymph nodes and spleen may occur as the body tries to compensate for the reduced function of the neutrophilsNeutrophils are a type of white blood cell that plays a vital role in the immune response, especially in fighting bacterial infections. They are part of the body’s first line of defense against pathogens.. Blood count changes such as anemia can also be observed.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of Trapped Neutrophil SyndromeA syndrome is a group of symptoms that occur together and indicate a specific disease or condition. A syndrome can be caused by various factors and is often complex in its diagnosis and treatment. usually begins with a thorough clinical examination and a detailed medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. to evaluate the symptoms and the course of the disease. However, due to the non-specific symptoms, a definitive diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. can be difficult.

A complete blood count is crucial to determine the number of neutrophilsNeutrophils are a type of white blood cell that plays a vital role in the immune response, especially in fighting bacterial infections. They are part of the body's first line of defense against pathogens.. In TNS, the blood count typically shows neutropeniaNeutropenia is a condition in which the number of neutrophils, a type of white blood cell, is abnormally low in the blood. This can increase the risk of infection in dogs and cats., i.e. a reduced number of neutrophilsNeutrophils are a type of white blood cell that plays a vital role in the immune response, especially in fighting bacterial infections. They are part of the body's first line of defense against pathogens.. Other abnormalities such as anemia can also be detected.

To confirm the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients., a genetic test can be performed to detect the presence of the specific mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. in the GFI1 gene that is responsible for TNS. This test is particularly useful for distinguishing affected dogs from non-affected carriers.

Therapy

A causal therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. for Trapped Neutrophil SyndromeA syndrome is a group of symptoms that occur together and indicate a specific disease or condition. A syndrome can be caused by various factors and is often complex in its diagnosis and treatment. does not currently exist. Treatment therefore focuses on alleviating the symptoms and supporting affected dogs in coping with infections.

Antibiotics can be used to treat and prevent bacterial infections that commonly occur due to reduced immune function. In severe cases, intravenous antibiotic therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. may be necessary.

SupportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. care, including a nutritious diet and regular veterinary care, is crucial to improve the overall well-being of affected dogs. In some cases, immunostimulants or growth factors may be considered, although their effectiveness is limited.

Prognosis and follow-up care

The prognosis for dogs with Trapped Neutrophil Syndrome is generally unfavorable. Most affected dogs develop severe infections in puppyhood that are often untreatable. Life expectancy is usually severely shortened, and many dogs die or must be euthanized before reaching adulthood.

The severity of symptoms can vary from dog to dog, even if the genetic mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. is identical. Some dogs have a relatively better quality of life if diagnosed early and treated adequately, but the long-term prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. remains difficult.

Prevention

The most effective method of preventing Trapped Neutrophil SyndromeA syndrome is a group of symptoms that occur together and indicate a specific disease or condition. A syndrome can be caused by various factors and is often complex in its diagnosis and treatment. is genetic testing of breeding animals. Through the use of genetic tests, carriers of the disease can be identified and excluded from breeding to prevent the transmission of the defective gene.

Responsible breeding management, including avoiding inbreeding and carefully selecting breeding pairs, can significantly reduce the risk of giving birth to affected puppies.

Education and awareness in the breeder community are also crucial to improve understanding of this genetic disease and to promote the necessary measures for control and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring..

Outlook on current research

Research into Trapped Neutrophil SyndromeA syndrome is a group of symptoms that occur together and indicate a specific disease or condition. A syndrome can be caused by various factors and is often complex in its diagnosis and treatment. (TNS) in Collies has made significant progress in recent years. TNS is a genetic disease caused by a mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. in the GFI1 gene. This mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. prevents neutrophil granulocytes, a type of white blood cell, from leaving the bone marrow and entering the bloodstream. The disease leads to immunodeficiency, which makes affected dogs susceptible to infections. Current studies focus on understanding the genetic mechanism and molecular basis of this disease.

Much of the current research focuses on improving diagnostic methods and developing ways to correct genes. Genetic tests are already available and help breeders control the spread of the disease. Scientists are also exploring the possibility of gene therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. as a potential treatment method. This therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. could theoretically replace the defective gene copy with a functioning one, which could alleviate or possibly cure the symptoms of the disease.

In addition, the role of environmental factors and other genetic predispositions that can influence the severity of the disease is being investigated. Researchers are working to create more comprehensive genetic profiles that could help to better predict the risk of TNS in Collies. Such profiles could enable breeders to make more targeted decisions to further reduce the spread of the disease.

There are also efforts to establish internationally standardized protocols for breeding Collies to minimize the risk of spreading TNS. These protocols include the use of genetic testing as a standard procedure in the breeding of Collies. Collaboration between international research groups is crucial to preserve the genetic diversity of the breed while protecting the health of the animals.

Another area of research is the development of therapeutic approaches that focus on strengthening the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. of affected dogs. Experimental treatments that support the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. could help improve the quality of life of dogs and reduce susceptibility to infections. Such therapies may prove useful when used in conjunction with genetic correction measures.

In summary, research into TNS in Collies is heading in a promising direction. The development of new diagnostic and therapeutic approaches could lead to better management strategies for this disease in the near future. This could enable affected dogs to live longer and healthier lives.

Frequently asked questions (FAQs)

What is Trapped Neutrophil Syndrome (TNS) in Collies? TNS is a genetic disease that occurs in Collies and is caused by a mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. in the GFI1 gene. This mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. prevents neutrophil granulocytes, a type of white blood cell, from leaving the bone marrow and entering the bloodstream. This leads to an immunodeficiency that makes the dogs susceptible to infections.
How is TNS diagnosed? TNS is mainly diagnosed by genetic tests that can detect the specific mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. in the GFI1 gene. These tests are particularly important for breeders to identify affected animals and prevent the spread of the disease.
Can all Collies be affected by TNS? Yes, theoretically all Collies can be affected by TNS, as the disease is genetic. The likelihood of a dog being affected depends on the genetic makeup of the parents. However, genetic testing before breeding can minimize the risk.
What symptoms occur in dogs with TNS? Dogs with TNS often show symptoms of immunodeficiency, such as recurrentRecurrent refers to a disease that repeatedly returns or worsens after a temporary remission or improvement. infections, Growth disorders, and general weakness. The disease can also lead to Refusal to eat, Weight loss, and a reduced life expectancy.
Is there a cure for TNS? There is currently no cure for TNS. Treatment focuses on alleviating the symptoms and supporting the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body.. However, research is being carried out into possibilities for gene therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions., which could enable a cure in the future.
How can TNS be prevented in Collies? TNS can be prevented through responsible breeding practices that use genetic testing to identify carriers of the mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits.. Breeders should only breed dogs that are not carriers of the mutationA mutation is a permanent change in the DNA sequence (genetic material) of an organism. In dogs and cats, mutations can lead to genetic diseases or desirable changes in certain traits. to prevent the spread of the disease.
Are all Collie breeds affected by TNS? TNS is primarily known in the Longhaired Collie, but can also occur in other Collie breeds. It is important that breeders of all Collie breeds consider genetic testing, especially if cases of TNS are known in the pedigree.
How common is TNS in Collies? The exact frequency of TNS in Collies is not fully known, but varies depending on the region and breeding populationIn veterinary medicine, the term population refers to a group of animals of a particular species living in a specific geographic area or environment.. However, genetic testing and responsible breeding practices can significantly reduce the frequency of the disease.
What support is available for owners of dogs with TNS? Owners of dogs with TNS should work closely with their veterinarian to develop a treatment plan that alleviates their dog’s symptoms. There are also specialized veterinary clinics and research centers that can offer support in the care of affected dogs.
Is there hope for future treatments for TNS? Yes, research is making progress in the development of gene therapies and other innovative treatment approaches that could improve the management and treatment of TNS in the future. These advances offer hope for affected dogs and their owners.