Comparative Neurology Program

Sensory Neuropathy:
An emerging disease in Border Collies

What is Sensory Neuropathy?

Sensory Neuropathy in Border Collies was first reported in the veterinary journals by Wheeler in 1987. Since then several more cases have been reported and recently neurologist around the world have seen an increasing number of cases. Affected dogs begin showing symptoms at 5-7 months of age and in all cases progressed to the point where euthanasia was necessary. Post mortem examination of the nerves showed sensory neuropathy.

A neuropathy is a disease of the peripheral nerves. The peripheral nervous system (PNS) is comprised of the nerves that emerge from the brain and spinal cord to supply sensation to the skin and control the muscles. Disturbances of the PNS can be solely sensory, motor or both. Sensory neuropathies, or diseases of the sensory nerves, are rare and manifest as loss of coordination, joint laxity, loss of proprioception (inability to know where the limbs are in space), and inability to perceive pain. Animals with sensory neuropathies will often self-mutilate their limbs. Although we can't be sure exactly why, human's with similar conditions often describe a tingling or burning sensations in their fingers and toes. Dogs may perceive a similar tingling or pain which causes them to chew at their toes.

What else might look like Sensory Neuropathy?

This disease can be mistaken for spinal cord disease in the neck which can cause loss of coordination and pain perception. It is different from a disease of the spinal cord changes in the reflexes, and it is rare for spinal cord disease to cause lack of pain perception when the dog can still walk.  The other consideration would be an infectious disease, such as Toxoplasmosis or Neosporosis that have affected the peripheral nerves.  This can be differentiated with blood tests performed by a veterinarian.  Lastly, this disease has been mistaken for loss of blood flow to the feet or simply a skin disease

Sensory Neuropathy
Border Collies with sensory neuropathy show misplaced limbs and laxity of the joints. Self inflicted wounds can also be noted on this dog's left hind limb.

Is Sensory Neuropathy hereditary?

When a disease shows up consistently in only one breed, genetics is probably playing a significant role in the disease.  Though it is too soon to say conclusively, Sensory Neuropathy appears to be hereditary in the Border Collie and is most likely a recessive trait.  In a recessive disease, both parents of an affected pup can appear normal.  All animals have two copies of each gene, one that is inherited from the mother and one that is inherited from the father.  A dog that has one normal gene and one gene that causes the disease is a carrier of the trait.  They show no symptoms because the one good gene is enough for their brain to develop normally, but they will pass that bad gene on to about half of their offspring.  If a carrier dog is bred to another carrier, then some of the pups (one quarter of them on average) will get a bad gene from each parent.  Without one good gene to carry the day, the peripheral nerves cannot function normally and the unlucky pup has sensory neuropathy. 

How do we find the gene responsible

The goal in dealing with hereditary diseases is to identify the gene responsible. Then we can develop a DNA test that will aid breeders in avoiding the disease in the future. Genes contain the genetic code that programs everything about an animal from the color of their coat to how their brains develop. Genetic disease occurs when a mutation interferes with the ability of a gene to function normally. Each dog has an estimated 20,000 individual genes, any one of which could contain a mutation that causes Sensory Neuropathy. We now have the tools, however, to find the mutation responsible for such diseases.

How can I help?

If you have a litter with a pup you believe might be affected, please contact us . We can help your veterinarian in determining whether or not this is the problem in your pup. In return, we would ask your help in collecting the samples and information necessary to continue searching for the gene responsible for this disease. Your continuing support will be necessary to achieve our goal.

Any information provided to us will be kept strictly confidential

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Gene Map

We now have the tools to find the gene responsible for hereditary diseases in dogs. The arrow points toward the region of a chromsome where a disease causing gene has been located.

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