HEALTH IN TIBETAN SPANIELS
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Tibetan Spaniels are a very healthy breed.
the only accepted health problem is that of a hereditary blindness, called Generalised Progressive Retinal Atrophy. This is called PRA for short.
PRA3 is one particular form of this hereditary disease.
Over 40 years ago there were Tibetan Spaniels diagnosed with blindness, either partial or full which was caused by PRA. These diagnoses were made by clinical examination where the eye specialist vet looked into the eye and could see that there was atrophy of the retina. Decisions were made within the breed that efforts should be made to try and control this hereditary condition. To this end, and with co-operation of the Breed Clubs, the British Veterinary Association,(BVA) and The Kennel Club(KC) a Health testing Scheme was set up. The Scheme requires that breeders and owners should take their dogs annually to be clinically examined for PRA, the results of this would be recorded by the KC and published in the Breed Record Supplement so that everyone would be aware of which dogs had been tested and their results.
Unfortunately PRA is often late onset and so that dogs and bitches may well have been bred from before a positive PRA result came to light. As technology progressed it became apparent that there could be a possibility of a DNA test, which would be a one off test to tell us if a particular Tibetan Spaniel was clear of PRA or a carrier, or indeed, likely to develope the disease.Until now carriers were only known if mated together and produced a clinical case of PRA. The Tibetan Spaniel fraternity around the world raised funds for the research and sent in samples from clinically diagnosed cases and their siblings as well as clinically clear cases. Last year- (2013) the Animal Health Trust (AHT) announced that it had finally found a DNA test for a form of PRA which they call PRA3. This particular mutation (form) was found in 60% of the cases used in the research, the other mutation(s) of the disease found in the remaining 40% remain unknown. (Information from the AHT website,(see below). The PRA3 mutation is recessive, which means a dog needs to inherit two copies of the mutation to be clinically affected with PRA3.
PRA3 is a late onset condition and clinical signs can usually be detected by an ophthalmologist when the TIbetan Spaniel is from 4-7 years of age. Current estimates suggest that up to 25% of TIbetan Spaniels carry a single copy of the PRA3 mutation but will not develope PRA3. This estimate is based on samples submitted to the AHT for the purpose of research and are unlikley to be representative of all Tibetan Spaniels.
PRA3 DNA testing has with the agreement of the Breed Clubs, the KC and the AHT been set up as a health scheme, which means that as of October 2013 the results of any samples sent to the AHT for PRA3 testing will be sent directly to the KC and be published in the KC Breed Record Supplements. The results will also be printed on KC registration papers with progeny from 2 Tibetan Spaniels tested clear of PRA3 being noted as Hereditary clear of PRA3.
Tibetan Spanielists in the UK now have 2 health schemes for PRA, a DNA test for PRA3 and a clinical test for the other form(s) of PRA. It is essentail that clincial eye testing takes place as it is the only way of diagnosing PRA mutations which are not recognised by the PRA3 DNA test. The advice from the AHT is as follows:
It is advisable for all breeding dogs to have their eyes clinically examined by a veterinary ophthalmologist prior to breeding and throughout their lives, with at least one examination occurring when the dog is at least 8 years of age, so that any cases of PRA caused by additional mutations can be detected and that newly emerging conditions can be identified.
(Written by Ms Sheila Thomson and reprinted with permission from the Tibetan Spaniel Club of Scotland).