Trapped Neutrophil Syndrome In Dogs

Trapped neutrophil syndrome (TNS) is hereditary autosomal recessive neutropenia known only in Border Collies that has compromised the immune system, resulting in chronic infection in affected collies. In this case, neutrophils are produced in the bone marrow (the most abundant leukocytes that fight infections) but an efficient release of them into the bloodstream is hampered. Of late, the contributory mutation (VPS13B Exon 19 ‐ chr13) has been detected and a DNA-based diagnosis is now available.

Most commonly, affected dogs present symptoms of immune dysfunction between the ages of 6-12 weeks. mildly affected dogs do not show signs of disease until 1- 2 years of age. The severity of Neutrophil syndrome can differ and any of the body systems can be affected: respiratory, musculoskeletal, gastrointestinal, skin, etc. The affected pups have typical facial deformities including a slender, elongated skull resembling that of a ferret and when compared to unaffected littermates, they are usually smaller.

Trapped Neutrophil Syndrome is an Autosomal Recessive condition in dogs means that they must receive one from each parent (two copies of the mutated gene) to develop the disease. Overall, carrier dogs are heterozygous and they do not manifest clinical signs of the disease but when bred with another carrier of the same gene, the resulting pups having the disease are high. In fact, each pup born to this pair has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy of the VPS13B gene mutation.

• Abnormally narrow head (ferret-like)
• Inability to nurse properly
• Smaller than other puppies
• No weight gain normally
• Lack of interest in surroundings
• Weakness
• Depression
• Lameness
• Swollen joints
• Higher than normal body temperature

There is no specific cure for TNS however it can be treated to relieve symptoms

TNS treatment in dogs focuses on putting brakes on the disease progression, reducing the suffering of the pets, and improving the quality of life for the pet

For infection: Metronidazole (Flagyl, Protostat, Metizol, Metrogel)

NSAIDs like Carprofen, Meloxicam, Firocoxib, Deracoxib, Etodolac

Pain-relieving medications: Mantadine, Tramadol, Gabapentin, etc

Immunosuppressive or anti-inflammatory medications: Cyclosporine, mycophenolate mofetil, leflunomide, or Azathioprine

Optimizing your pet’s Compromised Immune conditions must be the top priority

Diet: Wholesome, nutritious diet formulated for the dog’s size and lifestyle

Supplements: Immune-boosting supplements

• The carrier dog has one allele (copy) of the normal gene and an allele of the mutant gene.
• The carrier dogs are unlikely to develop Trapped Neutrophil Syndrome (TNS) but it can transmit to its pup's genetic code with a 50% probability.
• During breeding, identified Carriers' dogs are bred to dogs that did not inherit the same mutation.
• Carrier to carrier should be completely avoided as 50% of their offspring in a litter is expected to be affected.
• Genetic screening tests are available and the mutation responsible can be revealed directly. Recent methods provide higher accuracy and can be done for dogs of any age.

Border Collie, Puppies

1. Causes:

The cause of TNS is a mutation of the VPS13B Exon 19 ‐ chr13, which is only found in Border Collies.

2. Mortality:

The affected puppies without treatment will die within 4 months of age.

3. Diagnosis:

• A complete blood count (CBC), chemistry profile
• PCR-based assay
• Bone marrow biopsy
• X-rays

4. Prognosis:

The trapped neutrophil syndrome can be mild to severe. Prognosis is typically good for a complete recovery in mild cases. However, this condition is usually fatal within the first year of life.

Contact your vet right away, if you notice any of the following:

• Abnormally narrow head (ferret-like)
• Inability to nurse properly
• Smaller than other puppies
• No weight gain normally

Foods to avoid:

• Tougher meats/fatty foods/high in fiber
• crunchy or chewy or greasy, oily, spicy foods
• Dairy products like milk, yogurt, etc
• Roasted nuts and bread products

What to feed:

• Provide easily digestible lean cuts of meat. - Beef, pork, fish, and poultry (cooked and drained of excess fat)
• Milk and milk products (Cottage cheese, yogurt), Calcium-fortified foods, and beverages
• Plant-based protein sources –Chickpeas, green beans, Lentils, cooked legumes
• Vitamins: Broccoli, Brussel sprouts, spinach, kale, papaya, strawberries, and pineapple
• Calcium-rich foods and supplements: Green leafy vegetables, broccoli, White beans, salmon, Sardines, etc

Unfortunately, TNS is almost always fatal within the first year of life. Euthanasia may be a better option if the pet is having frequent infections and pain to humanely spare your pet from suffering.