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http://www.optigen.com/

New Mutation Test for prcd PRA Is Now Available
Please read this information carefully and refer below for added notes specific to each breed. Please understand that we are counting on you to review this information completely. If you have questions, email, fax or mail them. We will not be able to handle phone calls.

Some of the information about prcd-PRA on other pages of this website is now out-of-date. We are in the process of updating and redesigning the site. Please check back in a week or so.

June 1, 2005
Press Release


Ithaca, NY: OptiGen, LLC, proudly announces identification of the gene causing canine prcd-PRA (progressive rod-cone degeneration form of Progressive Retinal Atrophy). The cause of this inherited blinding disease, occurring in at least a dozen purebreeds, is one specific mutation in the coding sequence of the gene. OptiGen now offers a direct gene mutation test (mutation test) to detect the prcd-PRA status of any dog among affected breeds.

This success results from years of extensive investigation by Dr. Gus Aguirre and Dr. Greg Acland and their research staff at Cornell University. Essential cooperation from multiple breed clubs and more recent participation by OptiGen completed the team. The research data defining this mutation are being prepared for publication in a scientific journal. Commenting on future work, Dr. Aguirre says: “Going forward, the biological action of the prcd gene in the retina will be studied, with goals of understanding the basis of this disease and searching for treatments or even, eventually, cures.”

The new OptiGen prcd mutation test accurately detects the presence or absence of the mutant prcd disease gene copy. It replaces earlier OptiGen DNA-marker-based tests (marker tests) that detected changes in coding sequences of genes located near to and inherited with (linked to) the prcd gene. OptiGen henceforth defines result status based on the mutation test as “Normal/Clear” or “Carrier” or “Affected.” Designation of Patterns A(A1), B(B1), and C(C1) for previous marker tests are retired.

While the basic research of Aguirre and Acland spans decades, OptiGen’s prcd-PRA test evolved over the last 7 years, with the first marker test offered to Portuguese Water Dogs in 1998. Initially it detected false positive alleles. Subsequently, improved versions of the marker test analyzed coding sequence changes in more tightly linked genes and greatly reduced the frequency of false alleles. This improved marker test accuracy and gave an excellent estimate of prcd-PRA frequency within affected breeds.

A crucial set of information for proof of the prcd mutation was generated by OptiGen, according to Dr. Jeanette Felix, President. Between March 1, 2004 and May 31, 2005, OptiGen had added the potential mutation test to the standard marker test for all new samples from prcd-affected breeds in order to validate the identity of the mutation in large populations. Analysis now shows that the results are consistent between the marker test and the potential mutation test.

The prcd mutation test further improved accuracy over the marker test for Labrador Retrievers and Miniature and Toy Poodles. Only these groups will receive updated test reports by mail during June. For all other breeds, there was no difference in the outcome between marker and mutation tests. Given this match, OptiGen will not retest other breeds originally tested before March 1, 2004. All test reports that gave Pattern status can be interpreted as: Pattern (A)A1 = Normal/Clear; Pattern (B)B1 = Carrier; Pattern (C)C1 = Affected.

Statistics based on the new mutation test show that the frequency of prcd-PRA varies substantially among breeds, ranging between 4% to 20% affecteds and 20% to 50% carriers. Dr. Acland emphasizes: “Genetic testing used in informed breeding programs clearly is essential for preventing new cases of vision loss. I expect more genetic tests will be developed as canine genome research accelerates. Breeders with experience using the prcd-PRA test will be eager to make use of all new genetic information.”

The prcd-PRA mutation test can be obtained following the same procedures as before - see www.optigen.com. As of June 1, 2005, the fee for the prcd-PRA test is reduced 25%, down to $195. Opportunities for discounts for litters, through online ordering and 20/20 Clinics continue.

The Morris Animal Foundation/The Seeing Eye, Inc. is a major sponsor of research by Drs. Acland and Aguirre. Grants from the NEI/NIH, the Foundation Fighting Blindness and The Van Sloan Fund and contributions from many breed clubs, organizations and individuals are gratefully acknowledged. Many club health committees and breeders gave welcome encouragement as well as invaluable samples and information on their breed lines.

OptiGen, LLC, is a private company established to provide canine genetic tests to breeders and owners of purebred dogs, their veterinarians and other veterinary specialists. OptiGen holds an exclusive international license to the Cornell University technology for prcd-PRA mutation testing, and exclusive and non-exclusive licenses to multiple other technologies developed at Cornell and elsewhere.

Added notes:

Price: The reduced price for the prcd-PRA mutation test is effective June 1, 2005. For samples received at OptiGen June 1st and after, credit cards will be charged the correct price, even if your online order indicated a higher price. If you sent a check and overpaid, you will receive a refund by mail. The 20/20 Clinic price now is $US156 or $US146.25 if ordered online. The Litter Rate price is $US135 per pup.

Re-Testing with the prcd-PRA mutation test: You do NOT need to request or order a re-test if your dog was tested already. Only a sub-group of Labrador Retrievers and a subgroup of Poodles needed a re-test. These have already been done by OptiGen at no charge and re-test reports are in the mail. No other dogs require a re-test.

Miniature and Toy Poodle:
If you had Poodles tested and reported by OptiGen PRIOR TO March 1, 2004, at no added charge to you, we retested these dogs with the new mutation test and are issuing updated reports. These will be mailed by June 6th. As part of the prcd mutation research, OptiGen had added the potential mutation test to the standard test as of March 2004, in order to validate the identity of the mutation in a large population of Poodles. Analysis now shows that the results are consistent between the marker test and the potential mutation test (except for a small and detectable subgroup, see below). Therefore, Poodles with reports dated AFTER March 1, 2004 do not need to be retested. For reports dated March 1, 2004 through May 31, 2005, Patterns A, B and C are equivalent to “Normal/Clear,” “Carrier” and “Affected.”

The prcd-PRA marker-based test for Miniature and Toy Poodles first was offered in June 2001. Test results were reported as Pattern A, B or C as determined by detecting DNA markers close to the prcd gene. We recognized and cautioned that there were false positives among these results. With the new prcd mutation test, cases of false positives now improve from Pattern C to “Carrier” or “Normal/Clear” and from Pattern B to “Normal/Clear.” Approximately 1 out of 40 or 2.5% of all tested Poodles improve status. Note: Reports issued after March 1, 2004 included the mutation test and are not at risk for false positives.

From the beginning, we cautioned that there are two or more types of PRA in Miniature and Toy Poodles. While the majority of clinically diagnosed PRA cases were detectable with our DNA marker test, some were not. We studied these variant PRA cases, trying to identify the genetic basis of the disease. Luckily, the new prcd mutation test solves many of these cases. We have proven that some dogs have a variant combination of DNA markers associated with prcd-PRA, yet have prcd-PRA disease caused by the same mutation as the more common prcd-PRA cases. There are three important consequences to this:

All prcd-PRA affecteds and carriers can be detected with OptiGen’s new mutation test, whether they inherited the common or the variant prcd-PRA markers.
A small number of Poodles (about 1 out of 150 or 0.6% of tested Poodles), previously reported as Pattern A or B, had variant prcd-PRA markers and now are revised to Carrier or Affected status based on the prcd mutation test. We alerted many of these owners earlier in the research.
There remain under study a small number of Poodles affected by a type of PRA that is not prcd-PRA.
The frequencies of “Normal/Clear” “Carrier” and “Affected” among OptiGen tested Poodles shift only slightly based on results with the new prcd mutation test. Statistics to date are very similar for Toys and Miniatures, showing 68% are “Normal/Clear,” 28% are “Carrier” and 4% are “Affected”.