ACC Voluntary prcd-PRA Registry

The Board of the American Chesapeake Club encourages all Chesapeake owners to have their dogs tested for the prcd-PRA gene unless both of the parents are proven clear of the mutant gene by test results (A/A1/Nor). OptiGen is the agent for this test.

Progressive Retinal Atrophy (PRA) is a disease that affects the tissue lining the back of the eye (retina). Over time, the retina deteriorates, until the dog can no longer see. As dogs can compensate fairly well when they lose their sight gradually, it is possible for a dog to seem normal and to be used for breeding until the blindness progresses to a degree that it is discovered. Frequently, Chesapeakes are middle-aged (four to seven years old) before the disease is discovered. Additionally, PRA in Chesapeake Bay Retrievers is caused by a recessive gene, the prcd or progressive rod-cone degeneration, gene. A dog can only have the disease if it has two copies of the prcd gene, one from each parent, and a dog can produce the disease in its offspring without being affected if it has only one copy (carrier) and is bred to another dog which is a carrier or affected with prcd-PRA. These two factors together (mature age at onset of symptoms, and recessive inheritance) make PRA difficult to remove from a breeding program. Affected or carrier dogs are often not discovered until after they have been bred from (sometimes many times) and passed the genes on to their offspring.

In 1999, a test was developed that allows Chesapeake Bay Retriever breeders to screen their dogs for prcd PRA. The test uses a small blood sample and looks for the presence of markers – tiny scraps of DNA – that indicate that the gene for PRA is present. Starting on March 1, 2002, OptiGen began using a new marker that gives reliable new information on prcd-PRA in Chesapeakes. Dogs tested before that date are listed as Patterns A, B, or C. Those dogs that were tested or re-tested after March 1, 2002 have their results listed as Patterns A1, B1, and C1. All dogs that tested Pattern A on the original test will test Pattern A1 with the current test. However, dogs tested as Pattern B and C could have improved results if re-tested with the new marker test. June 1, 2005 Optigen announced a new test that used the actual mutated gene instead of markers. Dogs tested with the mutation test will be rated Normal/Clear (Nor), Carrier (Car) or Affected (Aff). Information on the new test and on re-tests is available on the OptiGen website.

Pattern A/A1/Nor dogs are normal for prcd-PRA and will not develop this disease or pass it to offspring. Pattern A/A1/Nor dogs can be bred to any dog and, will not produce pups affected by the prcd form of PRA. Pattern B/B1/Car dogs will not develop prcd-PRA but are carriers of the mutant gene for the disease. Pattern B/B1 dogs should only be bred to Pattern A/A1/Nor mates in order to eliminate the chance of producing affected pups. Pattern C/C1/Aff dogs are homozygous for the prcd-PRA mutated gene and will eventually develop prcd-PRA if they live long enough. Pattern C/C1Aff dogs should only be bred to Pattern A/A1/Nor mates in order to eliminate the chance of producing affected pups.

Optigen tested 1500 dogs, of several breeds, with both the 3 marker test & gene mutation test. No dogs were downgraded and only three were upgraded. Optigen therefore has concluded that A1/B1/C1 ratings are equivalent to Normal/Carrier/Affected, without the percentage of error described above. A Pattern B/B1/Car or Pattern C/C1/Aff dog may be safely bred to a Pattern A/A1/Nor dog.

The ACC strongly advises that all dogs used for breeding continue to have annual CERF examinations. CERF exams check for many other hereditary eye disorders besides PRA. Breeders should also keep the whole dog in mind when conducting breeding programs, and strive to produce the best possible dogs with the least amount of hereditary defects. Dogs should not be bred solely based on their OptiGen results; nor should dogs be avoided in breeding based only on OptiGen results.

Links to additional articles on the OptiGen prcd-PRA test may be found on the Health page of this site and on OptiGen’s website, http://www.optigen.com/.

 

American Chesapeake Club PRA (prcd) Registry

OptiGen releases the list of Normal/Clear U.S. owned dogs to the Registry quarterly. Owners may send these results directly to us for earlier inclusion in the Registry. Owners of Pattern B1/Car and Pattern C1/Aff dogs, plus those owners in Canada or overseas, who wish to list their dog(s) either for public release or in the confidential database must contact Deb Rivas as those results are not released by OptiGen. Please provide us with a copy of the OptiGen report. Further information and updates on the test are available at OptiGen’s website, http://www.optigen.com/ or you may call them at 607-257-0301.

Deb Rivas - ACC prcd-PRA Registry Coordinator  -  chessie4me@aol.com

Due to the size of the prcd-PRA Registry, we have divided it up into multiple pages for quicker loading. It is in alphabetical order according to dog's registered name. Space does not allow us to add any titles to dog names. To view the current prcd-PRA Registry for the American Chespeake Club, click on one of the following links:

         

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