Canis ISSN: 2398-2942

Trapped neutrophil syndrome

Synonym(s): TNS, Cohen syndrome

Contributor(s): Daniel Batchelor, Simon Tappin

Introduction

  • Cause: autosomal recessive inherited condition, caused by mutations in theVPS13B gene.
  • Signs: affected Border collies typically present at a young age with developmental delay, pyrexia, joint swelling or pain, typical facial abnormalities, and neutropenia.
  • Diagnosis: easily confirmed by genetic testing.
  • Treatment: the few reported cases have responded at least temporarily to prednisolone and antibiotics.
  • Prognosis: some cases have responded favorably to treatment although prognosis remains guarded. Reported dogs all survived to adulthood with a good short to medium term outcome.

Pathogenesis

Etiology

  • Mutation (a 4 base pair deletion in exon 19) of the VPS13B gene; which results in premature truncation of the protein.
  • Autosomal recessive mode of inheritance.
  • Similar to Cohen syndrome in man and caused by mutations in the same gene.

Predisposing factors

General
  • If both parents are carriers then some puppies could be affected.

Pathophysiology

  • The VPS13B gene product is involved in vesicle mediated transport within cells but its exact function has not been determined.
  • Cohen syndrome in man is characterized by facial dysmorphism, microcephaly, slender extremities, mental retardation, small stature, developmental delay, delayed puberty, infantile hypotonia, neutropenia, myopia, and cataracts.
  • Affected dogs show circulating neutropenia but hypercellularity of the bone marrow.
  • The mechanism of failure to release mature neutrophils from the bone marrow in TNS is unknown.
  • In dogs inflammatory joint problems seem common and the reason for this is unknown.

Timecourse

  • Reported cases had been unwell for 1-28 days before presentation.

Epidemiology

  • There is an active screening program and a reported carrier rate of 11.3 % in the UK (rate varies geographically).

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Mason S L, Jepson R, Maltman M, Batchelor D J (2014) Presentation and management of Trapped Neutrophil Syndrome (TNS) in UK Border collies. JSAP 55 (1), 57-60 PubMed.
  • Shearman J R & Wilton A N (2011) A canine model of Cohen syndrome: Trapped Neutrophil Syndrome. BMC Genomics 12, 258 PubMed.
  • Wouda R M, King T J & Mackay B M (2010) Long-term management of trapped neutrophil syndrome in two border collies. Aus Vet Pract 40 (2), 58-63 VetMedResource.
  • Allan F J, Thompson K G, Jones B R, Burbidge H M & McKinley R L (1996) Neutropenia with a probable hereditary basis in Border Collies. N Z Vet J 44 (2), 67-72 PubMed.


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