Cerebellar Ataxia in Norwegian Buhunds
Researchers at the Kennel Club Genetics centre at the Animal Health Trust have identified a mutation causing Cerebellar Ataxia in the Norwegian Buhund. A DNA test will be available at the AHT DNA testing service from the 4th December 2017.
Cerebellar Ataxia can affect dogs as young as 12 weeks of age-Presenting with uncoordinated movement and head tremors. The disease is progressive, worsening over time. There is currently no effective treatment for this condition, with affected animals often euthanized on welfare grounds.
The causative mutation for this condition has been identified by researchers at the Kennel Club Genetics Centre at the Animal Health Trust (AHT), in collaboration with the Animal Health Trusts Neurology Unit.
The research tested 146 Norwegian Buhunds from both the UK and Finland; Carriers of this mutation were identified on both populations. The mutation was found to be present in the contemporary population
How is the disease inherited?
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 Cerebellar Ataxia mutation is located in the Norwegian Buhund; 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 Cerebellar Ataxia identifies if your dog is clear of the mutation, is a carrier of the mutation or has two copies of the mutation so is affected.
This allows breeders to avoid producing litters affected by this disease by ensuring that one of the breeding pair is clear of this mutation.
CLEAR: These dogs have two copies of the normal gene and will not develop Cerebellar Ataxia as a result of the Cerebellar Ataxia mutation we are testing for, although we cannot exclude the possibility that 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 Cerebellar Ataxia themselves as a result of the Cerebellar Ataxia mutation but they will pass the mutation on to approximately 50% of their offspring.
AFFECTED: These dogs have two copies of the Cerebellar Ataxia mutation and will have Cerebellar Ataxia caused by this mutation.
We cannot exclude the possibility that some dogs 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 that carriers are still bred with 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 Cerebellar Ataxia
On average, 50% of such a litter will be clear and 50% carriers; there can be no affected dogs produced from such a mating. 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 Cerebellar Ataxia.