Dogs with retinal folds only pass a CERF exam in breeds where it hasn't been shown conclusively to be connected to the serious forms of dysplasia. (or in breeds where it is thought not to be hereditary) In some breeds, like Labrador Retrievers, Samoyeds, and English Springer Spaniels, dogs with retinal folds are NOT given a CERF number. In these breeds, retinal folds are either common or dogs and bitches with retinal folds have had puppies with blindness and/or skeletal problems. There is no breed where geographic and retinal detachment forms of retinal dysplasia are certifiable.
As you know, cavaliers with folds do receive a CERF number. Folds in cavaliers are thought by many to be simple recessive, so yes, theoretically a test breeding could be done to see if the other dog was a carrier. Cavaliers have so many health problems, though, that breeding out retinal folds is not thought by many to be a top priority. The other problem with test breeding is that you would have to use stock that was examined early in life, as folds have a tendency to heal over by a year of age. They also may be missed at very young ages. So there is a small window in time in which one could be relatively certain that all folds would be seen. Folds are not thought to be recessive in all breeds. In Labradors and Samoyeds a combination of retinal dysplasia and skeletal defects has been described. This condition is known as oculoskeletal dysplasia. An autosomal dominant gene is thought to be responsible. Homozygous animals have skeletal changes and mild to severe retinal dysplasia while heterozygous animals usually have mild retinal dysplasia. Most of the veterinary ophthalmologists I have spoken to directly do seem to believe that there is some connection between folds and retinal detachment, even though it hasn't been proven in all breeds. They generally recommend not doubling up on dogs with folds to avoid the (however slight) possibility that dogs with more severe forms of dysplasia will be eventually produced. Leanne ========================================================= "Magic Commands": to stop receiving mail for awhile, click here and send the email: mailto:[EMAIL PROTECTED]?body=SET%20CKCS-L%20NOMAIL to start it up gain click here: mailto:[EMAIL PROTECTED]?body=SET%20CKCS-L%20MAIL E-mail [EMAIL PROTECTED] for assistance. Search the Archives... http://apple.ease.lsoft.com/archives/ckcs-l.html All e-mail sent through CKCS-L is Copyright 2002 by its original author.
