MDR1 Drug Sensitivity

One health issue found in some Silken Windhounds is sensitivity to the Ivermectin family of drugs; a trait shared with eight other dog breeds. When it was realized that some dog breeds had a portion of their population with adverse reactions to these drugs, it was not known why some animals were sensitive and others not. Washington State University located the gene responsible for adverse reaction in several dog breeds. As stated in the WSU web pages, "The problem is due to a mutation in the multi-drug resistance gene (mdr1). This gene encodes a protein, P-glycoprotein, that is responsible for pumping many drugs and other toxins out of the brain. Dogs with the mutant gene can not pump some drugs out of the brain as a normal dog would, which may result in abnormal neurologic signs. The result may be an illness requiring an extended hospital stay—or even death."

Through the cooperation of two dedicated research facilities, University of California – Davis identified breed distribution and prevalence for Ivermectin sensitivity (mdr1 mutation) using the test developed by WSU. Silken Windhound owners participated widely in the testing research by providing DNA samples taken via buccal cheek swabs of their dogs.

Testing for MDR1

WSU has developed in a simple cheek swab test that can be administered by the pet owner or veterinarian then sent to them for processing. When test results are known, it will permit veterinarians to administer alternative drugs to affected dogs rather than completely avoiding suspect drugs in susceptible breeds.

Testing to determine the status of Silkens in the gene pool will allow us to manage this issue so that no more MDR1-Affected dogs are produced. The ISWS highly recommends that breeding Silkens are tested to determine their status.

MDR1 testing is done by several labs:

For those outside North America, the following labs perform MDR1 testing:

More Information on MDR1

The published study showing results of this research can be seen here.

To see breed distribution information compiled by the University of California – Davis: http://www.vgl.ucdavis.edu/cghg/mdr1b.php

A list of drug sensitivities for dogs that carry the MDR1 mutation:
http://www.vetmed.wsu.edu/depts-VCPL/drugs.aspx