The MDR 1 Gene Mutation :: Your Australian Shepherd MAY Be At Risk

The MDR 1 Gene Mutation :: Your Australian Shepherd MAY Be At Risk

The MDR 1 Gene Mutation and your Austrailian Shepherd

We’d like to welcome and thank our guest article writer, Dr. Tatiana da Silva, DVM, for helping to
write this important article that all owners should be aware of!

Australian Shepherd owners more than likely have already heard about the
MDR1 Gene Mutation. But what exactly is it?  Why is it important to know if your
Aussie is a carrier of that genetic mutation?

MDR 1 stands for Multi Drug Resistance-1 and its mutation commonly affects
many herding related breeds. Not only can pure breed dogs, but also mixed-
breed dogs can be affected.

It is known that around 50% of Australian Shepherds (mini or standard) carry a
genetic mutation on the MDR-1 Gene that makes them more sensitive to certain
types of drugs including antibiotics, heartworm preventatives, anesthetics and
pain control medication, among others.

photo credit ZoeMarieTheAussie

Why is the MDR1 Gene Mutation important?

It is important to know if Aussies carry that mutation because if they do that will
impair their ability to limit the absorption of certain drugs and also slow down
the elimination of these drugs from the body. Basically, they have a higher
chance to get intoxicated by these drugs than non-affected dogs. That could
cause many severe signs such as disorientation, blindness, tremors and seizures
or even, in worse cases, death.

Ask Your Vet about the MDR1 Gene Mutation

If your veterinarian is aware that your dog is affected by or is a carrier of this
mutation, many precautions will be taken to avoid these symptoms from
occurring. For example, your veterinarian will most likely not use certain drugs,
or use them in lower dosage. He/she will also monitor your dog longer in case
certain drugs really need to be used.

photo credit ZoeMarieTheAussie

Get your Aussie tested

But how can you know if your dog is affected by the MDR1 gene mutation?
That is very simple. Just like humans can have DNA test performed, so can your
dog. DNA tests will not only show your dog’s genealogic tree, but more
importantly, test them for many genetic diseases, including the MDR1.
Now that you are aware of the importance of knowing if your dog is a carrier of
the MDR1 gene mutation, discuss with your veterinarian the best way to find out
for sure so you can provide your Aussie the best care.

If you want to know more about the MDR1 check out the website from the Washington State University School of Veterinary Medicine ( for some useful information.

If you’d like to see more from Dr. da Silva and her dog Zoe Marie, check out there awesome Instagram page!

Dr. Tatiana da Silva, DVM

Dr Tatiana da Silva graduated from the School of Veterinary Medicine at the University of Sao Paulo, Brazil in 2000. She practiced as a small animal surgeon in the University of Sao Paulo Teaching Hospital until she decided to move to Orlando, Florida in 2011. She has been working for Banfield Pet Hospital since validating her Veterinary degree in the USA. On her free time she loves to spend quality time with her wife and pets (3 dogs and 3 guinea pigs). She also enjoys working on her Australian Shepherd Zoe Marie Instagram’s page @zoemarietheaussie.

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