prcd-PRA TestFor: Chinese Cresteds
The gene mutation causing the prcd form of PRA is present in the Chinese Crested breed. Some dogs carry the mutation and some PRA affected Chinese Cresteds have the prcd form of PRA as detected by DNA testing.
More than one form of PRA:
The prcd gene is the cause of some, but not most, cases of PRA in Chinese Crested tested so far. There appears to be at least two different genetic forms of PRA in this breed, even though the clinical signs of PRA in all diseased dogs look similar. At this point, one form cannot be distinguished from another based on an eye exam. This is significant – a Chinese Crested that is Normal/Clear for prcd-PRA could still be at risk for having or carrying another form of PRA.
Frequency of prcd-PRA:
The exact frequency of prcd-PRA compared to other types of PRA in the Chinese Crested breed is not known. We do know that prcd-PRA carriers are not uncommon, but prcd-PRA does NOT appear to be the predominant disease type. More information on its frequency will be gathered as more dogs are tested.
Free testing for PRA affected Cresteds:
Continued research on Chinese Cresteds will identify the remaining gene(s) that cause other types of PRA. You can help if you have a Crested that has a documented diagnosis of PRA. OptiGen will test dogs that have a CERF or a clinical exam report by a certified veterinary ophthalmologist (ACVO or ECVO diplomate or comparable) stating that PRA has been diagnosed. First, the owner should submit a copy of eye exam records, along with the dog’s pedigree, to OptiGen for pre-approval. If approved, the owner would be instructed how to submit the dog’s blood sample and a statement permitting use of this dog’s blood sample for research purposes if it tests clear for prcd-PRA. There is no charge for testing PRA-affected dogs.
Which Cresteds should be tested for prcd-PRA:
Any Crested can be tested for its prcd-PRA status. It is most sensible to test any dogs that are related to or in line with a known prcd-PRA affected or prcd carrier dog. Due to this relationship, they are at risk for inheriting the prcd gene.
While annual eye exams by veterinary ophthalmologists are recommended for all breeds, regardless of genetic testing results, this is especially important for Cresteds since there is more than one form of PRA known to affect the breed.
Page last updated August 05, 2005
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