PRA Testing for Labrador Retrievers
PRA Testing for Labrador Retrievers
Frances O. Smith D.V.M.
Genetics Research Committee
Labrador Retriever Club


July 15, 1999

As our members will recall, the Labrador Retriever Club supported aggressively research dedicated to identifying Labradors which were carriers of, or affected by, Progressive Retinal Atrophy. Indeed the Club pledged the proceeds of several National Specialty raffles and hunt tests to support this research and to date has donated $10,753.00 to the Cornell research effort, and $1,000.00 to the Michigan State team. Throughout this period, the LRC Newsletter has reported on the progress of these efforts, having reported on several occasions the test’s availability was imminent, but delays inevitably must have occurred. In November of 1997, the Genetics Research Committee learned the estimated price for the test was twenty-five to thirty-five dollars. The news was met with enthusiasm by the Committee. In our opinion it offered hope for breeders who had no other practical means of eradicating PRA from their breeding programs, but would soon be able to do so affordably. Up until this time, ethical breeders had removed carriers and suspected carriers from breeding programs. In certain cases doing so meant abandoning years of investment.

In April, I learned the long-awaited PRA test would soon be available. Produced and marketed by Optigen, the test is a linkage test, (also known as a marker-based test) and will be offered at a much higher cost than originally anticipated-- approximately three hundred dollars. A representative of the Labrador Retriever Club was invited by Optigen to Cornell to be present at the time of the announcement. The Genetics Research Committee has been aware for some time how the test will work. It was the Committee’s recommendation that a representative of the Club not attend in that doing so would be an unnecessary use of Club funds. Furthermore, the Committee feels strongly that it would be inappropriate to appear as if the Labrador Retriever Club endorses one research project to the exclusion of another where the best interests of the fancy are concerned.

The Genetics Research Committee believes the Optigen test is a significant step towards the Club’s goal of eradicating the prcd gene in the Labrador population. We are disappointed by the delays and the limited availability to all breeders. The cost of the test will certainly limit the number of dogs screened by the individual breeder. Absent complete screening of breed stock, PRA will inevitably be a factor to contend with for several generations of Labradors to come. By no means should the recent announcement be construed as the solution to the Club’s goal of overcoming PRA.

The new test has the limitation of "false alleles." A dog tested and determined to be clear will be clear with absolute certainty. However, a dog with a genetically false marker may test as a carrier but in reality be normal. A dog with one true and one false marker may

be determined to be affected where the dog is actually a carrier. In short, the test is not 100% accurate and there will be a small number of false positives.

Both Dr. Aguirre at Cornell and Dr. George Brewer at Michigan State are independently conducting research to identify the gene or gene mutation responsible for prcd itself. Dr. Brewer estimates his research may produce the answer in 1 1/2 to 3 years depending upon staffing. It is the Committee’s recommendation that the Labrador Retriever Club offer financial support to Dr. Brewer’s research. To put these tests in perspective, the Optigen test is again a linkage marker based test whereas the ideal test will identify the gene or gene mutation responsible for prcd. The Genetic Research Committee feels strongly no organization should be given exclusive rights to offer such a test to the Labrador Community, and again it must be emphasized the Labrador Retriever Club will not "endorse" one organization’s research efforts to the exclusion of another where the advancement of scientific research is at stake. We have yet to be offered a definitive test that identifies the prcd gene. We are hopeful that, someday, such a test will be made available at a suitable price where there will be no financial impediment to evaluating all breed stock.

The Committee is delighted that Dr. George Brewer has accepted an invitation to speak at the Labrador Retriever Club National Specialty on October 15, 1999 in Chagrin Falls, Ohio. Please contact LRC Secretary Christopher Wincek if you wish to be added to the mailing list to receive the premium list for the National Specialty. Mr. Wincek can be contacted at P.O. Box 9, Clipper Mills, CA 95930. Email: administrator@thelabradorclub.com

The Genetics Research Committee of your Club therefore alerts you we have not come to the conclusion of the Labrador Retriever Club’s quest to put an end to PRA. Support for further research should continue. Hopefully future Club resources intended for the advancement of breed soundness will be earmarked accordingly.

On behalf of the Genetics Research Committee,

Frances O. Smith, D.V.M., Chairperson
The Labrador Retriever Club, Inc., is the single organization officially recognized by the American Kennel Club as the national parent club of the Labrador Retriever. The Labrador Retriever Club, Inc., was incorporated in October 1931, in the state of New York, and is not affiliated with any other association titled or claiming to be the National Labrador Retriever Club.