Degenerative Myelopathy part Two.
Degenerative Myelopathy in Chesapeake Bay Retrievers
by Claire McCall
[This article will appear in the UPenn Bellweather magazine and the ACC Bulletin]
The evening of October 22 found Dr. Sam Long deep in the heartland as he addressed the assembled crowd at the American Chesapeake Club’s annual retriever field trial in Stillwater, OK. Beginning about 1 ½ years ago, Dr. Long became aware of a small cluster of Chesapeake Bay Retrievers affected with degenerative myelopathy (DM), a neurodegenerative condition affecting the spinal cord. DM is well known to veterinary neurologists, since it has been seen in German Shepherd Dogs since the 1970s. However, very little progress has been made in elucidating either the etiology or the genetic basis of the disease in that breed. The owner and breeder of some of the affected Cheasapeakes located Dr. Long through Penn Vet’s switchboard and convinced him to take an interest in research that might lead to a genetic test for this debilitating disease. Some of the affected dogs are among the most competitive field trial Chesapeakes in the nation, but there are also Chesapeakes with DM that are not from field trial bloodlines.
Penn Vet alumna Wendy Shepard Chisholm, V’83, and American Chesapeake Club representative Melissa Shuman welcomed Dr. Long to the dinner and described the Club’s support for the DM research effort. Dr. Long took the podium and the room was suddenly quiet while he outlined the clinical course of DM, his experience with it in other breeds and in Chesapeakes, and ongoing research in his lab to determine the genetic component of this disease, with the goal of one day having a test that can be performed on a standard blood sample or cheek swab. To date, Dr. Long has identified 10 confirmed cases of DM in Chesapeakes; there are 3 additional likely (but not definitively diagnosed) cases. At the time of his address, a total of 40 blood samples from Chesapeakes had been provided. Even more impressively, through the hard work and enthusiasm of the Club, he has now built a pedigree around the affected cases that contains approximately 800 dogs, spanning 13 generations. The crowd followed up with lively questioning and was especially intrigued by the possibility of leveraging research being conducted at the University of Missouri on DM in Boxers and Corgis.
Two Club members turned their motel room into an impromptu hematology lab after the dinner, as owners brought 15 animals in for blood draws. On the first day of the field trial, Dr. Long and Melissa Shuman moved the “lab” out to the ranch where the retrieving stakes were being held. Aided by pleasant weather, keen interest, and a shrewdly chosen location between the parking and the competition, Dr. Long acquired samples from a total of 53 dogs during his trip to Stillwater, including several first- and second-degree relatives of affected dogs. The Club has already arranged for Dr. Long to update the Chesapeake community on his research at the 2008 conformation and obedience specialty show.
The work performed so far has progressed remarkably quickly, and the samples and pedigrees obtained may provide a crucial step in developing a new diagnostic test for this debilitating disease. The speed with which the project has continued is a testament to the enthusiasm and dedication of the American Chesapeake Club’s members, without whom none of this work would have been possible. Thanks to the owners and breeders concerned, we now stand a very real chance of producing a major breakthrough in the diagnosis and eradication of a disease which for 30 years has frustrated veterinarians and dog owners all over the world.
Melissa Shuman and Dr. Sam Long. I don't know the person sitting.