Sensory Neuropathy (SN)

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Sensory neuropathy (SN) in Border Collies is a severe neurological disease caused by the degeneration of sensory and, to a lesser extent, motor nerve cells. The mutation causing this disease was discovered by scientists at the Kennel club Genetics centre at the Animal Health Trust in 2015. Discounts are available when this test is bought as part of our combination deals.

The onset of the disease in affected Border Collies is from 2 to 7 months of age and signs include knuckling of the feet, self-mutilation wounds (caused by excessive chewing or licking due to the lack of feeling in the limbs) and a progressive incoordination of gait (ataxia). A progressive loss of sensation occurs in all limbs. Urinary incontinence and regurgitation can occur in the later stages of the disease.
Prognosis is poor, with no effective treatment available. As quality of life is severely affected, dogs with SN are euthanized on welfare grounds usually before two years of age.

How common is the disease?

Sensory Neuropathy is a rare disease, but cases have been reported in several countries worldwide.

To date we have tested 148 dogs since the test was launched in April 2015.
Below are the current statistics for this (June 2017).

Clear result = 151/192 animals tested

Carrier result = 32/192 animals tested

Affected result = 9/192 animals tested

How is the disease inherited?

Border Collie puppyThe 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 SN 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 SN as a result of the SN mutation.CARRIER: these dogs have one copy of the mutation and one normal copy of DNA. These dogs will not develop SN themselves as a result of the SN mutation but they will pass the mutation on to approximately 50% of their offspring.

AFFECTED: these dogs have two copies of the SN mutation and will be affected with SN.

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.

Breeding Advice

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: Forman OP, Hitti RJ, Pettitt L, et al. An Inversion Disrupting FAM134B Is Associated with Sensory Neuropathy in the Border Collie Dog Breed. G3: Genes|Genomes|Genetics. 2016;6(9):2687-2692. doi:10.1534/g3.116.027896.