Trapped Neutrophil Syndrome (TNS)
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Trapped Neutrophil Syndrome (TNS) affects the immune system. Pups with this condition show abnormal development of the head and face with a more elongated skull shape. The condition effects the immune system and pups fail to thrive and suffer from chronic infections. Usually the signs can be recognised with in the first few weeks of life.
The mutation causing this condition has been identified by researcher in Australia as a short deletion in the gene VPS13B.
How is the disease inherited?
The disorder shows an autosomal recessive mode of inheritance, which means that two copies of the defective gene (one inherited from each parent) have to be present for a dog to be affected by the disease.
Individuals with one copy of the defective gene and one copy of the normal gene, called carriers, show no signs of disease but can pass the defective gene onto their offspring.
When two carriers are crossed, 25% (on average) of the offspring will be affected by the disease, 25% will be clear and the remaining 50% will themselves be carriers.
Border Collie owners who use the TNS DNA test will be sent results identifying their dog as belonging to one of three categories. In all cases the terms ‘normal’ and ‘mutation’ refer to the position where this mutation occurs in Border Collies. It is not possible to learn anything about any other region of DNA from this test.
CLEAR: these dogs have two normal copies of DNA and will not develop TNS as a result of the TNS mutation.
CARRIER: these dogs have one copy of the mutation and one normal copy of DNA. These dogs will not develop TNS themselves as a result of the TNS mutation but they will pass the mutation on to approximately 50% of their offspring.
AFFECTED: these dogs have two copies of the TNS mutation and will be affected with TNS.
We cannot exclude the possibility that carriers might develop a similar condition due to other mutations they might carry that are not detected by this test.
Carriers can still be bred to clear dogs. On average, 50% of such a litter will be clear and 50% carriers; there can be no affected dogs produced from such a mating.
Pups which will be used for breeding can themselves be DNA tested to determine whether they are clear or carriers of SN.
For more information please contact us and we’ll be happy to deal with your enquiry.
Reference: A canine model of Cohen syndrome: Trapped Neutrophil Syndrome. Jeremy R Shearman and Alan N Wilton. Published: 23 May 2001 BMC Genomics 2011 May 23;12:258. doi:10.1186/1471-2164-12-258