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Old 04-21-2007, 07:02 PM
Finwe Finwe is offline
Active Pup
Join Date: Apr 2007
Location: Germany
Posts: 6
Default Collies, Shelties, Aussies, White Spepherds... - affected by the MDR1 gene defect

Hello from Germany!

I just registered and saw some discussions about the mutation in the important MDR1 gene. A mutation by which several breeds are affected.

This breeds are:
Collie (Rough and Smooth)
Australian Shepherd
White Shepherd
Silken Windhound
Old English Sheepdog
Border Collie
Mc Nab
Longhaired Whippet
and perhaps some more including mixed breed dogs

Not all breeds are affected the same. But the Collie is affected most - about every third Collie is affected (mutant/mutant - in Germany -/-) and more than 40% are carriers (normal/mutant - in Germany +/-). That leaves only about 20 to 30 % free dogs (normal/normal - in Germany +/+).

Because of the gene defect a affected dog doesn´t produce a certain protein, the Poly-Glycoprotein. This protein is important for the metabolism and detoxication. In a "normal" dog you would find this pGP within the blood-brain barrier but also in some other barriers like in the kidneys or the liver. A carrier perhaps may have less pGP than a free dog.
The lack of this protein means that many drugs wouldn´t be transported out of the body, but would show side effects - within the brain, the liver, the kidneys and so on. Some of this side effects may cause death.

This mutation is the reason for the so called "Ivermectin-sensitive Collie" and was known already in the 80th. Vets then already suspected an inherited gene defect or a defect within the blood-brain barrier. But it took nearly 20 years to show that it is both - the mutation was discovered and described in 2001.
This mutation was found within the MDR1 gene - MDR meaning "multi drug restistance". Up to now there are already more than 30 drugs known as dangerous. But the lists showing dangerous drugs are still growing - and sometimes because a dead dog was taken to a post mortem.

This is a very sad story. There are still vets not knowing about the defect gene and if they know they are sometimes helpless because there are so much drugs that can harm. And very often it depends on the dosage whether the drug helps or kills.
And to get more informations about this problems would mean to have animal experiments.

So the best way is to breed this defect gene out. That can be managed by just breeding to a normal dog. Your puppies then would be all normal/normal or normal/mutant.

Here in Germany research is going on at the University of Gießen (
But as for the States there is the University of Washington (
A list showing dangerous drugs you can find here:

And we started a certain project showing tested dogs of some breeds. So we hope to inform and encourage others to test their dogs. And we inform about litters were no affected puppie will be.
We would gladly show your dogs, too.

For more informations please look here:

Thank you for your attention and have a nice day!

Kris, Germany
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