Optigen DNA test for Retinal Dysplasia/Dwarfism in the Samoyed
NEWSFLASH 10/15/2010 - from Sue Pearce-Kelling at Optigen
I am really happy to relate that the ACVO has officially adopted the recommendation to clear the Samoyeds (and Labrador retrievers) that have focal/multifocal retinal folds if the dogs are shown to have Normal/Clear DNA test results for the RD/OSD mutation. I attended the ACVO annual conference last week in San Diego and this was specifically discussed. The recommendation in the "blue book" i.e. the "ACVO Ocular Disorders Presumed to be Inherited in Dogs 2009" for Samoyeds with retinal folds reads as follows:
"The breeding advice for Labrador Retrievers and Samoyeds diagnosed with "retinal dysplasia - folds" will be changed from "No" to "Breeder option" if the owner of the dog provides the CERF office with results of the DNA test for the affected dog, showing that it is not a carrier of the oculoskeletal dysplasia (OSD) mutation. For DNA testing contact Optigen®: RD/OSD test. Optigen LLC, Cornell Business and Technology Park, 33 Thornwood Dr., Suite 102, Ithaca, NY 14850. Telephone: 607-257-0301.
SCARF has received word from Optigen (www.optigen.com), that a test for inherited Retinal Dysplasia (RD)/ OculoSkeletal Dysplasia (OSD, ie., dwarfism) is now available.
From the Optigen website: "After extensive research in the laboratories of Drs. Greg Acland and Gus Aguirre, ACVO diplomates and genetic investigators at Cornell University and the University of Pennsylvania, the mutations responsible for OSD in the Labrador retriever and Samoyed have been identified."
I'd like to add here, that without the bravery shown by a couple of Samoyed breeders over a decade ago, this mutation would not have been found.
What will this DNA test mean to Samoyed Breeders?
This test will allow breeders to know for certain whether those puppy foldsseen at 8 - 12 weeks are linked to the RD associated with dwarfism. And even if your dog is shown to be a carrier - breeders can still breed around the situation by breeding to a clear Samoyed and then testing your future offspring with the DNA test. Within a few generations, all offspring could be clear.
What is the mode of inheritance?
Unlike the XL-PRA gene in Samoyeds, the gene for RD/OSD is NOT sex linked.
It is an "autosomal dominant with incomplete penetrance". This means that some carriers will show phenotypical evidence of the disease (like retinal folds) and others will not show folds when they are eye tested (ie., CERF). However, both types of carriers may pass on the defective gene to their offspring.
Are all dogs with folds or Retinal Dysplasia carriers of the gene that causes dwarfism?
No. But this new DNA test will be able to tell you if they are "normal", "carriers" or "affected" with the gene for RD/OSD.
Note-there are other forms of Retinal Dysplasia/retinal folds which ARE NOT associated with the dwarfism. This test is ONLY for the RD associated with OSD (dwarfism). To read about the various types of Retinal Dysplasia:
Can Optigen use the sample I previously submitted for the XL-PRA test to test for RD/OSD?
Yes, in some cases that will be possible if enough of the sample is left. Check with Optigen if you have previously submitted samples on your dogs.
More information is available on the Optigen website: