Geriatric Dog and Informative Family Projects – Anna Marzolino and Beth Verner
Dr. Meryl Littman and colleagues at the University of Pennsylvania have been updating the DNA Bank inventory, including samples from affected animals, geriatric dogs, and dogs of the Informative Families and Wheagle Colony. There are currently 228 samples in the Bank. Most samples are from affected animals, with 97 dogs already on the Open Registry (OR), and another 26 dogs that should be. Some diagnoses are pending and some phenotypes are as yet unknown (the dogs are still too young). The dates of birth for samples in the Bank are from 4-17-83 to 10-31-04; the median date of birth is 3-22- 1993. Based on DNA in the Penn Bank, following are Dr. Littman’s observations related to the Geriatric Dog and Informative Family Projects.
“The most interesting/surprising yet confusing/vexing finding is that the geriatric dogs’ phenotypes are not all normal. Many (n=24) of the geriatric samples show changes consistent with the changes we see in the PLE and/or PLN dogs. Some geriatric dogs have rare fetal glomeruli (mild RD). Other geriatric samples (n=33) were tagged as “normal” but not all owners of those dogs submitted samples for histopathology or had recent screening tests done.
The histopathology findings that we do have warn us that it may be difficult to interpret which dogs’ DNA samples will be useful as completely “normal”. We also learned that there does not appear to be an age cut-off for genetic expression of these changes.
These new findings have been discovered because of our work for the Bank; in the past, geriatric dogs were generally not tested by screening tests or necropsy since we would have thought we were “out of the woods”. We have not as yet put geriatric dogs on the OR that had these abnormal changes on histopathologic examination.
Since the Phenome Project is looking for samples from affected and unaffected siblings, we checked the Bank’s inventory for such pairs. It will be hard to know at what age to consider a sibling unaffected or “normal” (10-12 yrs old may be too young).
Two of the Informative Families included litters whose members were all affected. We learned that RD was a complication in one PLE/PLN Family. We purposely chose Families that were hit hard by PLE/PLN, so that there would be no question of the inheritance and classic nature of their disease, however, this caused entire litters to be affected, without normal siblings. However, the aunts and uncles in those Families may yield affected as well as unaffected dogs, and those dogs will be very important to follow. They are currently still too young to evaluate their phenotypes.
In the third Informative Family, not all the litter is affected, but the “normal” dogs are still only 9 years old. No new cases of PLE/PLN or RD have been identified in the Families since the last report. Good news is that cooperation is increasing for sending in missing DNA samples.
Other than possibly from the Informative Families and Wheagle Colony, there are no other affected and unaffected sibling pairs currently in the Bank. But if/when the Phenome Project finds genetic markers from suitable pairs, the large number of affected and unaffected samples in the DNA Bank can be checked for those markers, thereby helping to validate the findings. We can share samples if we have one of a sibling pair here. Great news is that genomic technology has gotten so sophisticated and that the Wheagle Colony and Informative Family dogs are almost old enough for geneticists at Penn and Missouri to study soon and really learn valuable information!”
Respectfully Submitted
by
Beth Verner for the Informative Family Project and
Anna Marzolino for the Geriatric Dog Project
