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prcd-PRA Test 

 For: American Eskimo Dog

American Eskimo Dog Reliable identification of dogs that do not carry disease genes is the key to eliminating inherited recessive diseases, like prcd-PRA. The OptiGen prcd test for American Eskimo Dogs provides almost 100% identification of these dogs. Called "genetically clear", "noncarriers" or, more formally, "homozygous normals," such dogs pass the normal gene on to all their pups with a very high probability - which means that their pups have a very low risk of being affected with prcd. These "clear" dogs can be bred to any mate - even to a prcd-affected dog that may be a desirable breeding prospect for other reasons.

 

Homozygous means both copies of the gene in your dog are the SAME - both normal or both prcd. A carrier has one normal and one prcd gene.

The OptiGen prcd test is done on a small sample of blood from the dog. The test analyzes the specific DNA mutation causing prcd-PRA. The OptiGen test detects the mutant, abnormal gene copy and the normal gene copy. The result of the test is a genotype and allows separation of dogs into three groups: Normal/Clear (homozygous normal), Carrier (heterozygous) and Affected (homozygous mutant).

Possible results using the OptiGen prcd test for American Eskimo Dogs

Genotype

Risk Group

Significance For Breeding

Risk of prcd Disease

Homozygous Normal Normal/Clear Can be bred to any dog, extremely low risk of producing affecteds Extremely Low
Heterozygous

Carrier

Should be bred only to Normal/Clear to remove risk of producing affecteds Extremely Low
Homozygous Mutant

Affected

Should be bred only to Normal/Clear to remove risk of producing affecteds Very High
 

Questions and Answers:

  1. Is there more than one type of PRA in American Eskimo Dogs?
    The only known form of inherited PRA in American Eskimo Dogs is prcd-PRA. Other retinal diseases can be confused with prcd-PRA. For example, multi-focal retinopathy is a non-inherited disease seen in this breed. Multi-focal retinopathy is usually asymmetric (different symptoms in each eye), shows foci of what appears to be healed inflammation, and can cause a generalized retinal atrophy. Also, cases of acquired retinal disease due to various non-genetic causes like trauma, active work, etc., can be confused with PRA. The OptiGen prcd-PRA test will accurately distinguish dogs with acquired disease or multi-focal retinopathy from truly prcd-PRA affected dogs.

  2. What is the usual age at diagnosis?
    American Eskimo Dogs are typically diagnosed with prcd-PRA around 4-6 years of age. As more dogs are examined, it’s likely that even younger and older dogs will be discovered showing first signs of prcd-PRA. The progression of PRA in this breed can be quite slow, sometimes allowing some useful vision even late in life.

  3. How frequent is PRA in American Eskimo Dogs?
    There is no definitive estimate of the frequency of PRA in American Eskimo Dogs, although CERF data give some indication of the frequency relative to other breeds. CERF data from 1991-1999 were compiled by the American College of Veterinary Ophthalmologists (ACVO) Genetics Committee to give frequencies of reported eye disease diagnoses for each breed. Among American Eskimo Dogs with CERF exams, almost 9% have retinal atrophy – either generalized or suspicious. For comparison, the Portuguese Water Dog is listed at 2.3 % with retinal atrophy and OptiGen finds 3.8% of tested dogs are  genetically affected and 35% are genetically carrier. At the higher end, the Nova Scotia Duck Tolling Retriever is listed at 6.9% with retinal atrophy and OptiGen finds 7.0% of tested dogs are genetically affected and 45% are  genetically carrier. There is certainly bias in both the CERF and OptiGen estimates due to voluntary testing, non-random sampling, and extent to which the breed is CERF examined. All the same, the two estimates do correlate a high or a low incidence.

  4. Are there any proven cases of false negatives or false positives in this test?
    So far, there are no cases of false negatives in the test used on American Eskimo Dogs. However, as larger numbers of dogs are tested, it is possible that such a case will be identified. It is also possible that a few will be discovered with a retinal disease that is not genetic prcd-PRA. They might have another, rare form of PRA or an acquired retinal degenerative disorder. OptiGen will follow-up on any American Eskimo Dog that is diagnosed with some type of PRA but does not test as genetically affected. And, so far there is no known case of a false positive in American Eskimo Dogs. That means - we have not yet seen a genetically  carrier dog that might actually be genetically normal/clear, nor a genetically affected dog that might actually be carrier or even normal. The prcd mutation test provides highly accurate results.

  5. Should carrier or affected dogs be bred?
    OptiGen test results should be used in a responsible breeding program. The genetic status of each breeding dog should be known. Carrier and affected dogs with other desirable traits can be bred safely, but only to a genetically “normal/clear” dog in order to prevent prcd-PRA disease. There is no logical reason to eliminate carrier or affected dogs from a breeding program, if they are valued dogs. Please return to the "prcd- PRA Test - General Information" for more on breeding strategies.

  6. What American Eskimo Dogs were used in the research to develop their specific prcd-PRA test?
    Almost one hundred American Eskimo Dogs from North American multi-generation pedigrees, including many PRA affecteds, were studied to develop and validate this test. Blood samples from these dogs were submitted to the research laboratory at Cornell University. Extensive analysis of many DNA markers linked to the prcd gene proved that the disease in this breed is caused by the prcd gene. Dogs used in this study were registered at different size standards (Standard, Miniature and Toy), and with both registries (UKC and AKC). The identity of prcd-PRA in these pedigrees reflects their common ancestry, as is well known, and is confirmed by pedigree analyses. To the best of our knowledge, the OptiGen test can be used on purebred, registered American Eskimo Dogs worldwide.

  7. Who funded the research leading to this test?
    Financial support for this research conducted in the laboratories of Drs. Gregory Acland and Gustavo Aguirre at The James A. Baker Institute, Cornell University, was provided by The Morris Animal Foundation/The Seeing Eye, Inc., The National Institutes of Health, and The Foundation Fighting Blindness. OptiGen, LLC, collaborated with screening and final refinements for a commercial test.

  8. Why is the American Eskimo Dog PRA test restricted by patent and license rights?
    Universities routinely review research discoveries made by their faculty and staff for commercial value. When appropriate, the discovery is patented and use of the patent is licensed for business purposes. Cornell Research Foundation, Inc. owns the patent for all DNA-based genetic tests for prcd-PRA. (1998 - prcd-PRA US Patent No. 5,804,388; prcd-PRA Canadian Patent No. CA2306194; prcd-PRA U.K. Patent No. 2 341 926) Since 1998, OptiGen, LLC, has had an exclusive license arrangement with Cornell Research Foundation to commercialize the test.

  9. What determines the price of a genetic test?
    The price applied to a test reflects the entire cost of performing the test, including laboratory, office and administrative staff inputs and materials used, and the infrastructure to ensure quality control, reliability and stability of the business. The price also includes a portion for obligatory royalty payments to Cornell Research Foundation, Inc.  OptiGen’s price range for various tests is $80 to $195 per test.

  10. Can any other laboratory offer this test?
    Under the lawful protections of the U.S., Canadian and U.K. patents and exclusive license, no other North American nor U.K. laboratory may offer a test for prcd-PRA in any breed.

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OptiGen®, LLC · Cornell Business & Technology Park · 767 Warren Road, Suite 300 · Ithaca, New York 14850
Tel: 607 257 0301 · Fax: 607 257 0353 · email: genetest@optigen.com or optigen@clarityconnect.com
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