Shaking Puppy Spongiform LeucoEncephaloMyelopathy (SLEM)
Border Terriers affected by SLEM show severe tremors predominately in the hind limbs, this creates a side to side shaking.
Postmortem examination of the pups with SLEM show Vacuolation (Spongiform) of the Nerve fibers (Leuko) in the brain (Encephalo) and the spinal cord (Myelopathy).
Collaborating scientists at the University of Missouri, the Animal Health Trust and at Wisdom Health, have identified a mutation responsible for this disease in the Border Terrier.
The SLEM mutation is recessive; this means that a dog must inherit 2 copies of the mutation, one from each parent, to be clinically affected by SLEM.
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.
It is only possible to identify carriers with DNA testing.
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.
Breeders using our 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 in the DNA where this SLEM mutation is located in the Border Terrier; it is not possible to learn anything about any other region of DNA from this test.
What does the DNA test tell me?
The DNA test for SLEM identifies if your dog is clear of the mutation, a carrier of the mutation or is affected by the mutation.
This allows breeders to avoid producing litters affected by this disease by ensuring that one of the breeding pair is clear of this mutation. This test can also be used to confirm a diagnosis of SLEM.
CLEAR: These dogs have two copies of the normal gene and will not develop SLEM as a result of the SLEM mutation we are testing for, although we cannot exclude the possibility they might develop a similar condition due to other causes or the effect of other, unidentified mutations
CARRIER: These dogs have one copy of the mutation and one normal copy of DNA. These dogs will not develop SLEM themselves as a result of the SLEM mutation but they will pass the mutation on to approximately 50% of their offspring.
AFFECTED: These dogs have two copies of the SLEM mutation and will have SLEM caused by this mutation.
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.
We recommend that for the first few generations after the development of a DNA test you still breed with carriers to avoid reducing genetic diversity.
Dogs carrying this mutation can be breed from safely to avoid producing affected puppies. Carriers of the mutation should be mated to dogs that have a clear result; such a mating will not produce any puppies affected with SLEM
On average, 50% of such a litter will be clear and 50% carriers; there can be no affected dogs produced from such a mating. Please note these percentages apply to a statistically significant number of puppies. The distribution does vary from litter to litter.
Pups which will be used for breeding can themselves be DNA tested to determine whether they are clear or carriers of SLEM.