I graduated from Washington State University College of Veterinary Medicine. This probably makes me somewhat biased as to the Veterinary Clinical Pharmacology Laboratory at Washington State University in Pullman, Washington.
But this lab has made great strides in research that has saved many dogs in the herding breed group — like Australian Shepherds — from life-threatening drug reactions.
Some dogs, especially herding breeds, have a mutation in the MDR1 gene, which leaves them with multi-drug sensitivity, a genetic predisposition to have adverse effects from commonly used medications.
This mutation can cause loss of balance, depression, disorientation, excessive salivation, dilated pupils, abnormal eye movement, blindness, tremors, inability to stand up, coma, breathing problems and even death when given a commonly used drug from the “problem drug” list.
Fortunately, WSU’s Veterinary Clinical Pharmacology Laboratory discovered the cause and invented a method (MDR1 test) to determine if a dog has this disease.
About three out of four Collie in the United States have the mutant MDR1 gene. The frequency is about the same in Australia and France, so it’s likely that most Collies around the world have the mutation.
The MDR1 mutation has also been found in Australian Shepherds, Shetland Sheepdogs (Shellies), old english sheepdogs, English Shepherds, german shepherds, Long-haired Whippets, Silken Windhounds and a variety of mixed-breed dogs.
The only way to know if a dog has the mutant MDR1 gene is to have the animal tested. As more dogs are tested, other breeds will likely be added to the list of affected breeds.
Breeds known to be affected by the MDR1 mutation include the following:
» Collie, 70%
» Long-haired Whippet, 65%
» Australian Shepherd, 50%
» Australian Shepherd, Mini, 50%
» Silky Greyhound, 30%
» English Shepherd, 15%
» Shetland Sheepdog, 15%
» German Shepherd, 10%
» Crossbreeding of livestock breeds, 10%
» Mixed race, 5%
» Old English Sheepdog, 5%
» Border Collies,
WSU has identified many mixed-breed dogs with the MDR1 mutation. Some of them bear no resemblance to herding breed dogs. It is true that the MDR1 mutation has only been identified in herding breed dogs, so if your dog tests positive for the MDR1 mutation, it is highly likely that your dog has an ancestor that is part of the herding breeds. .
A puppy can be tested as soon as it is weaned from its mother. This is why they strongly recommend testing mixed-breed dogs for the MDR1 mutation before administering any of the problematic drugs listed on the lab’s website.
The MDR1 genotype test will determine if your dog has the MDR1 mutation.
The testing process is simple and no special training is required to collect the sample, which is obtained by brushing the cells from the inside of the cheek with a swab/cheek brush. You will receive swabs/brushes and sample collection instructions in the test kit, and an instructional video can be found on the lab’s website.
Test results are usually received within one to two weeks.
Click here for more information WSU Veterinary Clinical Pharmacology Laboratory, or contact the laboratory at [email protected] or 509.335.3745 to receive a test kit. The cost of the kit is $60.
Medications that cause life-threatening problems in dogs with the MDR1 mutation include some with combinations of flea and heartworm preventative products (those containing spinosad), as well as other antiparasitic drugs, some antidiarrheal drugs , some tranquilizers, some chemotherapy drugs and some pain relievers.
If you have a herding breed or possible crossbreed of a herding breed, this simple test can potentially save your dog’s life. Please let your veterinarian know if your dog has been tested and has an MDR1 gene mutation so they can avoid problematic medications that could harm your dog.
The WSU lab is very helpful by phone and email. Go Cougs!
— Dr. Bonnie Franklin is a rescue veterinarian who grew up in Santa Barbara. She obtained her doctorate in veterinary medicine through a joint program of washington state and Oregon State universities, a master’s degree in wildlife biology from Cal Poly, San Luis Obispoand carries out consultancy assignments with United States Forest Service. Click here for previous columns. The opinions expressed are his own.