Yesterday’s PRA announcement from Optigen is certainly a milestone in Glen of Imaal Terrier history but there are many questions to be asked still. They are arriving by email and telephone (thank you) and we’ll do our best to get the answers. The one thing that HAS to be emphasised at the moment is that the discovery of crd3 concerns only one form of PRA so testing should still continue at this time.
First answer to first question: Thankfully no, there will not be the issues of false negatives and false positives to contend with. “False” positives and negatives can arise when one is using a marker based test –where the test detects DNA changes near but not exactly at the mutation. The crd3 test is a mutation based test and is assaying the exact cause of the disease, not just markers that are linked to it. Of course, one must always keep in mind that there are other causes of PRA –there are plenty of mutations that have been identified in other breeds and it is always possible that another form or PRA could occur in the Glens. But at this point we are not aware of any in the Glen—only crd3. Let’s hope it stays that way!