The
English Shepherd
Pedigree Project
List of MDR1 results

A mutation in the canine multidrug resistance gene, MDR1, is associated with drug sensitivities in dogs related, even distantly, to collies. English Shepherds can have this mutant gene. Those dogs who carry two copies of the mutant gene are at most risk but dogs who only carry one copy are still at risk. There is more information at the bottom of this page, after the list of currently tested dogs.

English Shepherds are currently part of a study of the MDR1 gene being done at University of California at Davis . UC Davis will provide free sample test kits which are easy to use and will not hurt your dog. Contact:

Katy Robertson
Veterinary Genetics Laboratory
University of California at Davis
krrobertson@ucdavis.edu
(530) 752-3864
http://www.vgl.ucdavis.edu/research/canine/projects/mdr1/

for a copy of the free test kit. This testing is part of UC Davis' study and is perhaps not as extensive as the test kits you can purchase. It may take many months to get your results. You are doing UC Davis and the ES breed a favor by participating in the study; however, they are primarily a research lab and are not set up as a testing lab. If you have any question about your dog's drug sensitivity, consult your veterinarian and order a test kit from http://www.vetmed.wsu.edu/depts-VCPL/

MDR1 Genotyping Results

• Normal/Normal - These dogs do not carry the mutation, and will not pass on the mutation to their offspring. These dogs would not be expected to experience unexpected adverse drug reactions to normal doses of ivermectin, loperamide (Imodium(r)), and some anticancer drugs.
• Mutant/Mutant - These dogs carry the mutation and can not pass on a normal gene to their offspring. These dogs would be expected to experience toxicity after normal doses of loperamide (Imodium(r)), and some anticancer drugs, and high doses of ivermectin (greater than 50 micrograms per kilogram).
• Mutant/Normal - These dogs carry the mutation and may pass on the mutant gene to their offspring. These dogs may experience toxicity after normal doses of loperamide (Imodium(r)), and some anticancer drugs, and high doses of ivermectin (greater than 50 micrograms per kilogram).

• Ivermectin (Antiparasitic agent)
• Loperamide (Imodium(r); over-the-counter antidiarrheal agent)
• Doxorubicin (Anticancer agent)
• Vincristine (Anticancer agent)
• Vinblastine (Anticancer agent)