Progressive Retinal Atrophy - "Moving On"
In February 2009 it was confirmed that the Gordon Setter could suffer from a autosomal recessive mutation of a gene which causes PRA. In the Gordon Setter this has been found to have “late onset” that is it is unlikely to be displayed until 10 years of age, although ophthalmic testing could show early clinical signs from 7 years of age.
At this time the members of the British Gordon Setter Club together with the other breed clubs and associations all joined together to fund research into this condition via The Animal Health Trust (AHT).
Seminars were held with eminent speakers to ensure that the condition was understood and how it could be managed, although it was made clear that this was not a curable condition.
Many breeds suffer a form of PRA but the mutation in the Gordon Setter unfortunately did not match that of any other breed and so the AHT had to genotype the mutation and this could take many years of research and testing.
It is therefore amazing that the mutation was discovered in under 2 years and there is now a test available ( please see information below) to allow us to move forward with our breeding programmes which if sensibly managed will mean that PRA within the Gordon Setter can be eradicated completely although this will take several years.
The British Gordon Setter Club is extremely grateful to Cathryne Melluish and her team at the AHT who have worked so hard to bring the test to fruition.
The chart below shows how by using the knowledge of whether a dog is CLEAR, a CARRIER, or even AFFECTED, it should be possible to eliminate the condition in just a few generations. Consideration need to be given to the dog as a whole as we cannot simply breed for eye sight, we need to breed for type, temperament, good hips and overall good health.
Identification of Mutation for Progressive Retinal Atrophy in the Gordon Setter
A mutation responsible for the development of Progressive Retinal Atrophy (PRA) in the Gordon Setter has been identified by geneticists working in the Kennel Club Genetics Centre at the Animal Health Trust.
PRA is a well-recognised inherited condition that many breeds of dog are predisposed to. The condition is characterised by bilateral degeneration of the retina which causes progressive vision loss that culminates in total blindness. There is no treatment for PRA.
Owners report that their affected dogs develop night blindness in the first instance, which is indicative of a rod-cone degeneration, so we have termed this mutation rcd4 (for rod-cone degeneration 4) to distinguish it from other, previously described, forms of rod-cone degeneration.
The mutation is recessive and 19 out of the 21 Gordon Setters in our study that had clinical signs of PRA were homozygous (carried two copies) for this mutation, indicating it is the major cause of PRA in the breed. Two dogs in our study had PRA but did not carry the rcd4 mutation, indicating there might be another, genetically distinct, rarer form of PRA segregating in this breed.
The Animal Health Trust has developed a DNA test for the rcd4 mutation that will be available from Monday 14 th March, 2011. DNA test kits will be available to order online, via our website (www.aht.org.uk) from March 14 th. The price of the test will be £48 per sample, which includes VAT.
The research that led to identification of the rcd4 mutation was funded by many different organisations, including the Kennel Club Charitable Trust, the British Gordon Setter Club, the Gordon Setter Field Trial Society, the Gordon Setter Association, the Gordon Setter Club of Scotland and the LUPA project (www.eurolupa.org) as well as several individuals who have also contributed significantly. The AHT would like to thank sincerely all the organisations and individuals who donated funds to help support the research as well as all the owners who contributed DNA and information from their dogs.
Notes from Breed Council PRA Seminar
Dr. Jeff Sampson - 17th April 2011
The average age of on-set of blindness in PRA rcd4 affected dogs is 10 yrs which means it can occur anywhere within the age range of 7 – 15 yrs. This means that some dogs that’s DNA test results come back as Affected may never go blind as they will die of another cause before they reach the age at which blindness would have occurred.
There is at least 1 other mutation in the breed that can cause PRA in addition to rcd4 but this has only been found in a total of 2 dogs, neither of which are in the UK.
Affected dogs carry 2 copies of the gene; Carriers 1 copy and Clear none.
The Kennel Club administer several Health Testing Schemes including Hip Dysplasia, and for simple single gene conditions such as PRA rcd4. Once the KC scheme has been set up, the owner of the dog to be tested will complete a declaration on the form that accompanies the sample and is sent to the Animal Health Trust which gives their consent to the results being passed to the KC by the AHT. These results are recorded by the KC on their Registration database.
Publication of these results is achieved by several methods:
a. The Breed Record Supplement which is a quarterly KC publication
b. Printed on a dog’s registration certificate – to get a new Registration certificate with the results printed on it at nil cost owners can send the original registration certificate with a copy of the DNA Test results(on AHT headed paper) to KC at the Clarges St address.
c. On Registration documents of all subsequent progeny.
d. On the Kennel Club Web site. Results can be searched for on Health Results Test Finder using the registered name of the dog.
Advice issued by the KC Official Scheme
In Gordons Carriers are clinically normal & will not go blind.
All breeding stock should be DNA tested for PRA rcd4 before breeding.
If DNA test result is Clear, there are no restrictions on breeding in relation to PRA rcd4.
If the result is that the dog is a Carrier, there is no reason not to breed from a Carrier of PRA rcd4 if it is of good quality, type, temperament & general health to avoid the risk of losing breed type. You must not mate a Carrier to an untested Dog. Do not mate to another Carrier (1 in 4 puppies could be Affected and go blind) Do not mate to an Affected (1 in 2 puppies could be Affected and go blind). Mating Carrier to Clear will result in 50% of puppies being Carriers and 50% Clear, none of which will go blind. The breeder can then identify which puppies are clear & if of good type use those for breeding. If no good quality Clear puppies result, the dog can be breed again to Clear until good quality Clear puppy(s) produced for breeding.
If Affected, a dog can still be bred from if it is of good type, general health & temperament, using a Clear. This will produce all Carrier puppies, which can then enter the breeding programme as above if of good quality and they will not go blind.
There is no need to test all puppies before they are sold as the breeder can endorse those puppies’ pedigrees & have them DNA tested before breeding if either parent is Affected or Carrier to ascertain how to proceed when choosing a mate. The puppies pedigrees should initially be endorsed ‘Not to be Bred From.’ To do this the puppy must be in the ownership of the breeder at the time of endorsement; the breeder has to put in writing to the new owner that the pedigree is endorsed, why & under what circumstances it will be lifted and this has to be signed as acceptable by the new owner(s). If this is done the KC will not lift the endorsement without the breeder’s consent.
Once the KC scheme starts those dogs that have been previously tested can send a copy of their official results to the KC to be added to the Database & have new Registration issued.
At present ID verification is not compulsory but is preferable as this guarantees the sample has been taken from the dog in whose name the test is submitted. This is done by a Vet who checks the dog’s microchip or tattoo at the same time as they take the DNA sample.
We must not run the risk of losing breed type by excluding all but Clear dogs from the breeding programme. Both Carriers & Affecteds can be safely used if bred to Clear.
New DNA Testing Scheme for Gordon Setters
Following consultation with the Gordon Setter breed clubs, the Kennel Club has recently approved a new official DNA testing scheme for PRA (rcd-4) in the breed.
This test is offered by the Animal Health Trust and further details can be obtained from them at email@example.com
Copies of all future test results issued by the AHT will be sent directly to the Kennel Club, where the test result will be added to the dog’s details on the registration database. This will trigger the publication of the test result in the next available Breed Records Supplement, and the result will also appear on any new registration certificate issued for the dog and on the registration certificates of any future progeny of the dog.
Owners who have already had their dog(s) DNA tested for this condition may send copies of the test certificate into the Kennel Club and the data will be added to the dog’s registration details. In addition, if the owner includes the original registration certificate for the dog (not a copy) then a new registration certificate will be issued, with the DNA result on it, free of charge. Please send the DNA test certificates to:
The Health & Breeder Services Department
The Kennel Club
1 – 5 Clarges Street
For further information on this new scheme please contact Professor Jeff Sampson
21st April 2011
Copyright The Kennel Club
Reproduced with their permission
Gordon Setter Breed Council
Guidelines on PRA (RCD4) testing
Clinical Eye Testing is advised prior to each mating
Annual Eye testing is essential for stud dogs
In every mating one partner must be Clear
CCarrier x Carrier / Carrier x Affected / Affected x Affected should not be done
Advice will be revised on an annual basis, in consultation with the AHT
Over time, the ultimate aim is to eradicate PRA from the breed.
Puppy sale contracts should always be done which include breeding endorsements that can only be lifted by the Breeder.