Trapped neutrophil syndrome / TNS (VPS13B-related) - Border Collie / Huntaway / New Zealand Heading Dog

What does this test examine?

This genetic test analyses the VPS13B c.2893_2896del variant in dogs. The condition is known as trapped neutrophil syndrome, TNS, hereditary neutropenia, Border Collie trapped neutrophil syndrome and VPS13B-related immunodeficiency.

What does this condition mean?

In TNS, neutrophils, a type of white blood cell important for immune defence, are not normally available in the bloodstream. Affected puppies are often smaller or weaker than littermates, may develop a narrow elongated head and are more prone to recurrent or chronic infections. Fever, gastrointestinal signs, joint inflammation, lameness and failure to thrive can also occur.

Inheritance and result

This condition is autosomal recessive. A dog with one copy is a carrier and can pass the variant on. A dog with two copies is genetically affected with TNS.

Practical value of this test

This test is important for breeders because carriers can appear healthy, while two carriers together can produce affected puppies. The result helps identify carriers early, plan safer matings and clarify a genetic cause in puppies with infection susceptibility.

• Identifies clear dogs, carriers and genetically affected dogs.
• Helps prevent two carriers from producing affected puppies.
• Provides valuable information in young dogs with recurrent infections, poor growth or abnormal blood results.
• Supports transparent breeding selection and targeted management within affected lines.