MDR-1 Genotype Results

Multiple Drug Sensitivity (MDR1 gene) DNA Test
This DNA test identifies dogs that are sensitive to several medications. Shelties, Collies, Australian Shepherds, and Border Collies are a few of the breeds with this genetic mutation. Several commonly used drugs, ex. antiparasitic drugs (some used in heartworm preventatives), tranquilizers (acepromazine), and anti-diarrheal drugs (Imodium®) are a few of the drugs that may affect dogs with this genetic mutation. This test would provide useful, practical knowledge for every Sheltie owner, since knowing the status of each dog as clear, carrier, or affected would help a veterinarian determine which drugs to use or avoid in a particular dog.
As of March, 2008, 448 Shelties have been tested (Washington State University) with 11% being heterozygous (carriers) for the MDR1 mutation, and 1 % homozygous for the MDR1 mutation. Heterozygous dogs (carriers) exhibit sensitivity to drugs that is similar to or less than that of homozygous (affected) dogs. A complete list of drugs that may affect dogs with the MDR1 gene can be found at the following link: More information on the topic can be found at: and
The test can be performed using DNA from cheek brush collection that can be mailed-in by the owner.
Explanation of test 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®), and some anticancer drugs.

I just tested the following dogs and here are the results (from Washington State University)
Ch. Acadia's Bright Idea, RA, NA, NAJ Normal/Normal (MDR1-12080)
Ch. Acadia It's My Treat Normal/Normal (MDR1-12081)
Acadia On My Mind Normal/Normal (MDR1-12082)
Acadia Sunburst Merry and Bright Normal/Normal (MDR1- 12083)
Acadia Sweet Home Arizona Normal/Normal (MDR1 - 12084)

Acadia Sweet Emotion, AXJ,OA, OAF, PT was tested Normal/Normal a year ago and Heart Lake Acadia Le Roi de Cour is Normal/Normal by parentage.

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