The School of Biotechnology and Biomolecular Sciences at UNSW

The University of New South Wales

A leading research and teaching school with expertise in biotechnology, molecular biology, genetics, environmental microbiology, medical microbiology, immunology, biochemistry, protein chemistry and other areas of biological science.

Trapped Neutrophil Syndrome (TNS)

TNS was first described in border collies in New Zealand by Frazer Allen and Boyd Jones in 1996.  It has since been identified in show dogs and working dogs throughout the world with a very high incidence of carriers (over 10%).  This suggests that it goes back to the origins of the breed and may occur in other collie breeds.

TNS is an genetic, autosomal recessive condition that affecte the immune system.  Affected pups have Neutropenia which is a deficiency of neurophils.  Neutrophils are required for protection from infection.  Symptoms of TNS affected dogs can be quite variable and depend in part to types of infection the pup gets.

TNS is a condition where the bone marrow produces neutrophils but they are not released into the bloodstream. This results in an impaired immune system that cannot fight infections.

  • Symptoms are variable, many of the reported TNS puppies have been born looking normal but others have been born small.
  • Some puppies with TNS have been small and fine boned with narrow heads at some point but this may not be evident until approx 16 weeks.
  • A common first sign is a bad reaction to vaccinations with signs of fever.
  • Blood tests may show an abnormally low segmented neutrophil level but TNS can only be definitely diagnosed by bone marrow biopsy.
  • Any puppy that shows any signs of infection or failure to thrive is a possible case of TNS.
  • There is no cure for TNS and it appears to always be fatal eventually.  Antibiotic and steroid treatment can help affected dogs live a relatively active life.
  • TNS is an autosomal recessive condition.
  • The symptoms are extremely variable and will depend on the bacteria that the pup encounters. There may also be other genes that effect the disease expression.
  • Some dogs do not show symptoms until later in life.  Older puppies & young adult dogs diagnosed with immune system problems may have TNS so they should also be tested with the DNA test
  • There is no evidence that carriers of the TNS defect have increased immune problems.

Using the canidate gene approach Jeremy Shearman (PhD student) identified the gene and mutation that causes TNS in border collies. DNA testing has been done on over 5000 borders from around the world.  Testing is allowing breeders to reduce the frequency of the genetic defect in the population and reduce number of new affected cases.  Dr Wilton’s lab, where the research was done, is the only lab that can do testing currently. 

The research was support by donations from Border Collie Clubs and Pastoral Breed Health Foundation (UK)

1.Allan FJ, Thompson KG , Jones BR , Burbidge HM , McKinley RL. (1996). Neutropenia with a probable hereditary basis in Border collies. New Zealand Veterinary Journal. 44: 67-72

2.Shearman, JR, Zhang QY, Wilton AN.  Exclusion of  CXCR4 as the cause of Trapped Neutrophil Syndrome in Border Collies using 5 microsatellites on chromosome 19.  Animal Genetics  37: 89, 2006 doi:10.1111/j.1365-2052.2005.01413.x.

3.Shearman, JR, Wilton AN.  Elimination of neutrophil elastase and adaptor protein complex 3 subunit genes as the cause of trapped neutrophil syndrome (TNS) in Border collies. Animal Genetics 38, 188–189, 2007 doi: 10.1111/j.1365-2052.2007.01565.x