Recently the GRCA Health & Genetics Committee received a request from the GRCA Board of Directors to discuss recommendations regarding an age at which annual eye exams may be responsibly discontinued. In years past we believed that it was reasonably safe to say that the vast majority of genetic eye diseases for which Goldens are at risk could be detected by approximately eight years of age. Unfortunately, this is no longer the case. Although ophthalmologists have long diagnosed uveitis in Goldens, it was not until 2000 that a large study (Sapienza et al, 2000) defined a specific type of uveitis which is now known as "pigmentary uveitis" or "Golden Retriever uveitis."1
Unlike uveitis found in other breeds (or other types of uveitis in Goldens; it should be noted that Goldens can get uveitis that is not genetic and is CERF-able), pigmentary uveitis is not associated with an underlying systemic disease or infectious agents. Because of its unique characteristics; lack of association with underlying causes; and a familial link described in the above referenced paper – PU is strongly suspected to be an inherited disease. Thus, affected dogs are not CERF-able.
Unfortunately, pigmentary uveitis is a serious disease because the majority of affected Goldens have it in both eyes, and 46% of affected eyes progress to blindness due to glaucoma. It is a real quality of life issue for these dogs and their owners. Also unfortunately (because of the implications for breeding programs), the mean age at diagnosis is 8.6 years, with a range from 4.5 years to 14.5 years (data in this paragraph from Sapienza et al, 2000). This means that there is no age at which a dog can be deemed "safe" from developing PU. Further, most dogs that develop PU are actually past or nearing the end of their breeding careers.
To rise to the challenges PU presents, many conscientious breeders will need to change the way they approach eye exams and CERF registry in their breeding programs. It is not sufficient to stop doing eye exams when a dog is no longer breeding, because the dogs that have the most valuable data to offer are those whose age is measured in double digits.
So how can breeders respond appropriately to this disease? First, it is our responsibility to continue CERF-ing all dogs – male and female – that we have ever used for breeding throughout their lifetimes.2 An eye exam without registry with CERF is not adequate, because those to whom this information is most valuable are often several generations removed from the owner of what is now a grandparent or beyond; and breeders need to be able to independently look up the eye status of these dogs that are farther back in their pedigrees. Second, we must hold other breeders to the same standard in our dealings with them. If a grandparent or great-grandparent is not current on CERF (and is still alive), request that this be done. It is not only a reasonable request, it is also an ongoing responsibility that came with the decision to breed the dog years before. Third, when retired dogs are placed, require a yearly eye examination as part of the agreement. Most pet owners are happy to comply, providing they understand the reasons, and if the seller assists with referral, expenses, and/or transportation to local eye clinics.
There are a number of additional reasons that breeders should be submitting examination forms for CERF certification. Years ago, there was a reasonable argument to be made that CERF certificates were not as useful as the actual examination report. At that time, it was true that CERF certificates did not reflect "breeder option" findings such as distichiasis, entropion, and ectropion; so a CERF certificate could have obscured information of significance to interested parties. However, this has been rectified; and now the examination report itself is more likely to obscure information, than is the CERF certificate. This could happen, for example, in the case of certain types of cataracts which are not CERF-able – but when the exam form has not been submitted to CERF, it could be confusing and some may believe that the form of cataract in question is CERF-able. (Interestingly, sometimes even the examining ophthalmologist is not able to predict with certainty whether unusual findings are CERF-able.)
Further, the widespread availability of CERF data on various searchable websites (http://www.vmdb.org/verify.html) and AKC documentation (such as registration certificates and certified pedigrees) has added even more value to CERF-ing, and this is now clearly the gold standard for eye clearances. And at a cost that is less than half of a typical entry fee, there really is no excuse for conscientious breeders to neglect this responsibility. Again, although some breeders in the past chose not to submit examinations to CERF, this should no longer be considered to be fully meeting the highest standards that will best serve the breed. If all breeders were to comply with lifelong CERF- ing, those dogs that are affected with later onset diseases or other atypical findings would lose their current invisibility, and thus enable all of us to make more informed breeding decisions.
While the above recommendations are not spelled out specifically in the GRCA Code of Ethics, when one understands the special challenges and quality of life issues that serious diseases such as PU and PRA present, it should be clear that they follow the spirit of the COE. Over coming months, it is also anticipated that the GRCA Board of Directors will be evaluating some potential changes to the GRNews advertising policy which will reflect some of these considerations.
Finally, GRCA and GRF have been seeking researchers to help us better understand pigmentary uveitis, and most importantly, to try to identify the causative gene and develop a DNA test. We are currently requesting that owners of affected dogs and their unaffected relatives provide blood samples and pedigree information (this can be done confidentially if the owner prefers) to Wendy Townsend, DVM (see recruitment notice at "Pigmentary Uveitis Study") If Dr Townsend is not available, blood or cheek swabs can be banked at the CHIC DNA bank http://www.caninehealthinfo.org/dnabank.html (this is free for affected dogs).
The GRCA Health & Genetics Committee
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Footnotes:
1. PU certainly existed for perhaps decades prior to this, but this paper was the first to characterize it as an inherited disease in the breed, which then led to CERF’s decision not to certify affected dogs. Before 2000, affected dogs could receive CERF numbers.
2. Another eye disease long known to cause blindness in Golden Retrievers is Progressive Retinal Atrophy (PRA). PRA also has an older age of onset, typically between four and seven years of age. While estimates of prevalence in the breed remain below 1%, lifelong CERF-ing will also serve to help keep this disease in check. Owners of dogs diagnosed by a veterinary ophthalmologist as affected with PRA are requested to participate in research to help identify the causative gene or genes; please see " Progressive Retinal Atrophy "
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References:
Sapienza JS, Simó FJ, Prades-Sapienza A. Golden Retriever uveitis: 75 cases (1994-1999) Vet Ophthalmol. 2000;3(4):241-246.
