Thursday, November 29, 2007

Living with a Mutant

Fluff is a mutant. Normally it's not a big deal as she is pretty healthy. Right now it's a problem. She needs to have a tooth (maybe more?) removed, which means she has to be anesthetized. Unfortunately, her mutant status means most of the commonly-used pre-anesthetics are off limits to her. They're neurotoxic to mutants, and I like my girl to have a functonal nervous system. We tried masking her down (clamping a mask with a connection to a safe anesthetic gas to her face) for a procedure years ago, but she's the world's shallowest breather and most-determined-not-to-be-anesthetized dog. She kicked, thrashed, and blew out her anal glands in that attempt so we'd rather avoid that approach.

Fluff is not alone in her mutancy. She is what they call an MDR1 mutant. MDR = Multiple Drug Resistance. It means she can't get rid of certain drugs in her body like a normal dog can, so they build up and can cause nervous system damage or destruction. She cannot take Acepromazine and she cannot take Ivermectin for heartworm prevention. There are a whole host of drugs that must be avoided by the owners of these dogs. This mutation is extremely common in collies, shelties, Australian shepherds, miniature Australian shepherds, Silken windhounds and long-haired whippets. It also is present in other breeds and mixes that trace back to an affected breed. If you look at breeder webpages, you may see notations like "MDR1-NN" or "MDR1-NM" or "MDR1-MM" which means the dog was tested for its MDR1 status. "NN" means "Normal-Normal" or dog is completely unaffected by the mutation. "NM" or "MN" means one copy of the gene is Normal and one is Mutant. "MM" means the dog carries two copies of the mutant gene. It's not completely clear yet if NM dogs are affected by the mutant gene or if it takes two copies to fully express the defect. I personally would err on the side of caution and assume my beloved friend needs to avoid certain drugs.
To find a list of affected breeds and information on how you can test your dog to see if it carries the mutation, see This site also mentions some of the drugs to avoid if you own a mutant dog. Another site with an extremely useful list of drugs to avoid is

Be aware, if you own a mutant, that vets are not always thinking about the MDR1 mutation or may not even be aware of it. Just yesterday my vet and I were discussing Fluff's upcoming dental surgery and how to anesthetize her. My vet knew we couldn't use ACE as the pre-anesthetic so she mentioned she'd probably use butorphanol instead. Oops, that is on the list, too, so now we're a bit stuck because she's going to have to use a different drug in a protocol that is unfamiliar to her to anesthetize a dog she knows darn well is my heart dog, my Best Girl. Yeah, we're a little nervous now! Get the information. Give it to your vet. Make sure it's in your dog's chart at the vet. If you have to give drugs or have your dog anesthetized, ask what the drugs or anesthesia are, and check the list! If they won't change their protocol for your dog, go to another vet.

The above has been a public service announcement from Fluff.


Mrs. G. said...

Fluff is so cute. I will file this information away for the day when I get my next doggy. Good luck on Fluff's procedure.

kabbage said...

And Fluff is very much aware that she is very cute {smirk}. She thinks when people shriek "you are soooo cute" that she will be getting food, so she puts on a cute face anytime she meets new suckers, er, people. I never feed her, you know. She will tell you that and that's why YOU must feed her.

I suspect the procedure may be harder on my vet-friend (and me) than it will be on Fluff. I hope so, anyway!

Littlemankitty said...

I think Fluff is very cute for a dog. I hope I'm not a mutant. Well, I am a mutant, with the whole extra toes thing, but that doesn't affect the vet.

Kris said...

Hello from Germany!
My Finn is a mutant, too. He already managed to become 5 years without any bad illness and without the need to be anesthetized. Up to now he is a lucky one, because I know about others, who died from a wrong drug or while being under anaesthesia.
This mutation is a very serious one!
Therefore here in Germany we started a project - a homepage showing tested dogs and giving much informations ( - and we try to convince breeders to breed it out.
You are welcome to visit our homepage!