Retinal Folds Study

In the process of my regular breeding program I produced a litter in which several puppies had 1-3 folds in the lower part of the retina of one eye. These folds disappeared at 6 months, and the puppies could have had a CERF certificate at that point. Several ACVO ophthalmologists told me that the folds would disappear and that there was no reason to discard the puppies or their littermates from my breeding program. However, CERF was not of the same opinion. In conferring with several ACVO vets, including researchers at the University of Wisconsin School of Veterinary Medicine in Madison, I discovered that definitive research in this area had not been done. So I kept a puppy with folds from the litter to do research. Kozo is a pretty boy, but I have not shown him or used him as a stud dog except in this project. He lives with a friend as her house dog. We have bred him to one related female that had folds as a puppy and have now bred a daughter that had folds to a related male who also had folds as a puppy. The puppies were born 12/8/05.

The concern about retinal folds is that one type of fold, the so-called geographic folds, indicates the presence of a single copy of the gene that, when inherited from both parents, causes retinal dysplasia (RD). This genetic disease can cause detachment of one or both retinas, leading to blindness. It also can result in skeletal abnormalities, so it is designated RD-OSD. The purpose of my study was to determine if there is more than one type of retinal folds. Many ACVO ophthalmalogists told me that they could tell the difference between the folds I got and those associated with RD. My dogs’ folds were always restricted to one to several folds in the lower part of the retina. Three of these people cooperated with me on this study.

Our first folds to folds breeding resulted in 1 puppy out of 7 with the limited folds, none with RD or skeletal abnormalities. These dogs are now 14 years old if still alive. I have also bred Kozo to a littermate of the mother of this litter who did not have folds herself. We got 2 puppies with folds, again no RD or skeletal abnormalities. When bred to unrelated dogs, the mother of this second litter did not produce folds, nor did Kozo. In 2005 I bred a Kozo daughter with folds as a puppy (could be CERFed as an adult) to a male with the same condition, and got four surviving puppies (two died from exposure and two from difficult births- nothing that could be related to eyes). One had folds and one was controversial. So far there do not seem to be any health problems related to the presence of these so-called puppy folds. These dogs are now 6 years old.

Several years ago, a test for RD-OSD was released. I had several dogs, including the sire of the second folds to folds breeding tested. None of the dogs were carriers for RD-OSD. Because of this and because of a lack of affected females, I discontinued the study. From correspondence with other breeders, s well as my own experience, it appears to me that the “puppy folds’ I had are not uncommon and are not associated any pathology. There may be a third type of fold, so called geographic, as it occurs throughout the retina. Some dogs with this type of fold have tested clear for RD-OSD. The significance of this type of fold for their future health has not beenstudied.

All of my puppies have their eyes examined at 6-8 weeks, whether or not they are part of the study. And it is a 3 hour round trip to the nearest ACVO vet! No dogs that had puppy folds are part of my regular breeding program. Puppies that are part of the folds study were sold as family pets on the understanding that they could be examined as necessary for the study. Those kept for breeding were bred only as part of the study.

I am interested in hearing from anyone who has had puppies with similar folds and/or has information on how this condition is transmitted and on any problems they have seen in connection with this problem.

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