In September 2003 this leaflet below was sent out to all Cavalier Club Members. I was the Health Representative and I wrote it..............
I often wonder whether the problem could have been contained if breeders had been honest about their affected dogs and proactive in using the low cost scanning schemes when they started in 2004.
IMPORTANT PLEASE READ
There is a rapidly emerging awareness of an inherited condition in our Cavaliers.
Veterinary neurologist, Clare Rusbridge, and her team are conducting research into this condition and have found that 13 out of the 24 top stud dogs since 1998 have sired affected progeny. It is found in all colours, in all lines, and affects both sexes. While it remains unacknowledged it will continue to spread. This condition is called syringomyelia. This occurs when a Cavalier is born with not enough room in the space in the skull that contains the back of the brain. Damage is caused when fluid surrounding the brain is forced into the spinal cord.
The most common symptom is scratching on, or in the air near the shoulder when the dog is excited or walking on a lead. However this is not the only symptom and it is not always present. Affected dogs and bitches can be sensitive around the head, neck and front legs and often cry, yelp or scream for no apparent reason. They can develop a permanently twisted neck or have a wobbling gait in the hind legs and/or weakness in their front legs.
In severely affected cases the dog can suffer so badly that euthanasia becomes the only option.
Signs are usually noticed in dogs between 6 months and 3 years but it has been diagnosed in Cavaliers up to 10 years old.
At present the condition can only be identified by MRI scan or by clinical signs. There is not a test to identify carriers.
Studies of pedigrees suggest that Syringomyelia is caused by two genes that have to be carried by both parents for an affected dog to be born. Although dogs displaying signs of the problem were seen in the past, it is thought that the two genes came together in a significant way when descendants of two bitches, born in the 1950s, were mated together in the late 1970s.
Continual line breeding to the popular stud dogs of this era has increased the number of Cavaliers carrying both genes throughout the breed, and this includes many of the top stud dogs and brood bitches. It is these dogs whose genes dominate the pedigrees of the Cavaliers in our kennels, our homes and on our laps. No one is to blame because no one had the knowledge to identify the isolated cases as an inherited condition.
Information about individual dogs and bitches given to the Veterinary research team is confidential. Names have not and will not be passed on to anybody in the Cavalier Club or elsewhere
The problem is now widespread. There will be clear and carrier dogs and bitches in every line. Some breeders and stud dog owners may believe it is not their problem. In some cases they may not be aware that their dog or bitch has produced an affected Cavalier, and this is dangerous for the good of the breed. Owners are now being encouraged to inform the breeder if their Cavalier has a positive diagnosis. This problem, like MVD, is affecting us all.
It is what we do now that is so important. The researchers believe that it may be possible to develop a DNA test which will identify which Cavaliers are carriers of syringomyelia & which are clear.
DNA from extended families of dogs can be collected by blood sampling or, in some cases, cheek swab. Blood samples will be required from both clear and affected dogs and bitches. All donor dogs will be identified only by a code. It is hoped that it may also be possible to eventually produce a DNA for MVD from the same blood samples
The Cavalier Club hopes that any breeder asked to provide blood samples will co-operate with this vital research.
The search for a DNA test will take some time. The veterinary research team has provided what breeding advice they can (see below) At the moment we have no way of knowing whether our Cavaliers are clear or carriers unless they have already produced affected offspring.
This problem could continue to spread until there are very few clear dogs and bitches from which to breed. To act now to develop a DNA test will not only prevent pain & suffering, but will also make good commercial sense.
All dogs enjoy a good scratch. This may be because of a flea bite, ear mites or a skin condition. We must all resist the temptation of making ringside diagnosis.
Honest and frank discussion is what is needed if breeders and owners are to pull together to find a solution to this problem.
It is serious and it threatens all our Cavaliers.
Current Breeding Advice
Until we have a way of testing for the culprit recessive genes, this is what we recommend.
Identified by MRI (confirmed) or suspected on basis of clinical signs (scratching at shoulder area when walking on leash or when excited) Not to be used for breeding, stop breeding from affected cases now.
Unaffected known carrier (sire/dam and all offspring of an affected case) will have both genes. If mated with same will produce affected offspring. Use very sparingly. Mate only to unrelated dogs who have had no extended family history of syringomyelia. Keep other Breeders informed.
Unaffected dog (it is possible that all Cavaliers will be carriers of one or more recessive genes) Do not mate with closely related dogs. Keep track of all offspring The time of onset of symptoms varies greatly, from weeks to many years. If you breed an affected dog tell any other breeder involved.
For more detail please see the articles by Clare Rusbridge and Penny Knowler on the Club website: www.thecavalierclub.co.uk , the Club Magazine or send SAE to:
Mrs M Carter, 47, The Ryde, Hatfield, Herts. AL9 5DQ.
Information about dogs displaying symptoms of syringomyelia, especially those born prior to 1990, is still needed by the research team. Please contact: -
Clare Rusbridge BVMS DipECVN MRCVS
Stone Lion Veterinary Centre
41 High Street, Wimbledon, London, SW19 5AU
Tel. 0208 946 4228