Last Updated on February 28, 2014 : :

CA CONTROL SCHEME  GUIDELINES FOR THE LINKAGE-DNA TEST FOR CEREBELLAR ATAXIA

These Guidelines replace the previous CA Control Scheme and are considered a breed health testing scheme as referred to in the Kennel Club-approved Code of Ethics.

The current test, released by the AHT in March 2008, is a linkage-based test.  This means it looks for 2 markers close to the gene causing CA rather than the gene itself.  For this reason it is considered accurate to over 95%.  False positives are possible, false negatives have not been encountered.

These guidelines relate specifically to this test and will be revised accordingly when a gene-based test becomes available.

THE TEST

1. All dogs and bitches to be used for breeding must be tested, whether from known CA bloodlines or not.   This includes all imported dogs and bitches, British dogs that are used at stud abroad or whose semen is used for AI.

2. In 2012 a gene based test was developed by the genetics department at the AHT.  The ISCGB has been advised to continue using the Linkage based test for all breeding stock.

3.  All dogs and bitches must be permanently identified either by microchip or tattoo.  If a dog has both, both should be recorded on the submission form. The identity of the dog/bitch being tested must be verified by a third party (e.g. veterinary surgeon), who must sign the submission form to this effect.

4. The result of the test must be known BEFORE any mating takes place. Owners are advised to allow at least 4 weeks for the result to be available.

5.  All results of the CA test will be published by the Animal Health Trust (AHT) and by the Club on their websites. The AHT will only test samples on condition that the owner agrees to the result being published.

6. A copy of the certificate for the parents’ or appropriate ancestors’ CA test will be required for the litter to be accepted onto the Puppy Register.

7. Breeders must make available copies of the certificates for both parents of the litter for inspection by prospective owners.  In the case of dogs cleared by descent (i.e. progeny of two clear dogs) breeders must have available a copy of the certificates for the appropriate ancestors.

8. Further information and test kits may be obtained from Genetics Division, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, CB8 7UU. Tel: 01638 555621, Fax: 01638 555643.

9. The cost of the test is approximately £65, payable to the AHT.

THE IMPLICATIONS ON BREEDING

10. Dogs or bitches found to be carriers of CA do not necessarily need to be removed from a breeding programme solely on the basis of a positive test. However, breeding from a carrier should be considered as a last resort only, to enable a breeder to retain his/her bloodline and avoid the loss of valuable genetic material to our already small genetic pool.  It is imperative that the dog or bitch is otherwise of sufficient genetic merit in every other respect; that is, with appropriate conformation, temperament and true to type. 
 
11. It is  STRONGLY ADVISED, that a clear sibling be used for breeding IN PREFERENCE TO THE CARRIER, if of equal genetic merit,  conformation quality, temperament and true to type.  Inferior stock should not be used for breeding simply on the basis of being clear of CA.

12. If a carrier is to be bred, IT MUST BE MATED TO A CLEAR DOG OR BITCH.  This must be a TESTED CLEAR dog and not a dog cleared by deduction.

13. The risk of producing a carrier is 50:50  (see Appendix 1 for an explanation of the mode of inheritance) so breeders must take additional steps to safeguard the future of carrier puppies:

(a) All puppies in the litter must be tested, while the litter is still with the breeder.  Puppies must be fully weaned at the time of testing; that is, they must not be feeding from the bitch AT ALL.  This is to avoid any possible chance of contamination of the sample with the bitch’s milk, which would result in the bitch’s DNA being sampled rather than the puppies’. 

(b) New owners of carriers must be made fully aware of the dog’s carrier status and its implications. In particular, they must be made aware of the fact that a carrier status has NO HEALTH IMPLICATIONS for the puppy concerned, but is only relevant if the animal is to be bred.  It would be prudent, therefore, for breeders to make it clear to new owners that if they wish to breed they should not purchase a puppy carrying the CA gene.

(c) Fully endorse the litter and obtain signed confirmation from new owners that they understand the meaning of the endorsements. This must be done while the litter is still with the breeder. A signed copy should be kept by the breeder and a copy forwarded directly to the Kennel Club.

(d) Maintain regular contact with new owners of carrier puppies.

(e) Recommend neutering and consider bearing the cost of neutering carrier puppies.

14. If two dogs, cleared by test or descending from clear dogs, are mated, there is no need to test the litter, as the animals are expected to be clear.  However, if two dogs are assumed to be clear because they are not from known CA stock and are not tested, any breeding animal from such a mating must be tested, especially if mating to a descendant of known CA stock is considered. 

15. Breeders also need to consider that the disease has arisen through the mutation of a gene. There is no guarantee, therefore, that such a mutation may never occur again and spot testing of individuals is advisable.  We recommend spot testing when there are no tested dogs within 3 generations of the dog being considered for breeding.