Tuesday, June 17, 2014

MDR1 - do you know the danger?

What is MDR1? 
Multi-drug resistance 1, or MDR1, is a gene mutation found in many herding breeds.  This mutation causes toxic levels of certain drugs to build up in the brain; which leads to severe neurological problems, such as seizures and death.  It is estimated that around 75% of all collies have the MDR1 mutation, so all collie owners should be aware of which drugs are potentially harmful to their dogs.  If you are concerned that your collie, or herding breed, may have this mutation, there is now a simple, inexpensive DNA test offered.  For around $70, and with just a quick cheek swab, you can have your dog tested.

How does a dog end up with this mutation?  Each collie receives one allele, or gene, from each of it's parents.  Dogs that receive a "normal" MDR1 gene from each parent are +/+ (homozygous normal) or normal/normal.  All offspring from these parents will be clear of the MDR1 mutation, and will not be sensitive to the drugs listed below.

Dogs that receive a "normal" gene from one parent, and a "mutant" gene from the other parent are +/- (heterozygous).  While they are considered to be only carriers of the mutation, studies have found that they may also be sensitive to certain drugs.  These dogs will pass along the mutant gene to half of their offspring.

Dogs that receive a "mutant" gene from both of their parents are -/- or mutant/mutant. (homozygous mutant)  Dogs that are mutant/mutant are very sensitive to certain drugs, such as Ivermectin, and will pass on the mutation to all of their offspring.  According to the Collie Health Foundation and other leading researchers, the low dose of Ivermectin found in monthly heartworm medications will not cause a reaction.  However, many collie owners and breeders still choose to avoid use of any products containing Ivermectin, preferring to exercise caution instead.

Because of the need for caution, if your dog tests mutant/mutant or normal/mutant, you should make sure that any veterinarian treating your dog is aware of the risks of using certain drugs.  You will also want to make sure your dog does not ingest horse feces, because horses are treated with large quantities of Ivermectin and the drug is eliminated from their bodies in their feces.

 
Herding breeds at risk:
Australian Shepherds
Collies (rough and smooth)
English Shepherds
German Shepherds
Long-haired Whippets
McNabbs
Shetland Sheepdogs
Silken Windhounds
and any mixed-breeds with any of these breeds in their ancestry.

 

Dogs with the MDR1 Gene Defect should avoid the following drugs:

 Class A

Ivermectin substances (antiparasitics, such as Diapec, Ecomectin, Equimax, Ivomec, Noromectin, Paramectine, Qualimec, Sumex, Virbamec)

Doramectine substances (antiparasitics such as Dectomax)

Loperamide substances (antidiarrheal, such as Imodium)

Moxidectine substances (antiparasitcs such as Cydectin, Equest, Flagyl)

 

Class B (used only under CLOSE supervision of veterinarian):

Cytostatics (chemotherapy)

Immunosuppressive (Cyclosporine A)

Heart glycosides (Digoxine, Methldigoxine)

Opiods (Morphium)

Antiarrthymics (Verapamil, Diltiazem, Chinidine)

Antiemetics (Ondansetron, Domperidon, Metoclopramide)

Antibiotics (Sparfloxacin, Grepafloxacin, Erythromycin)

Antihistamin (Ebastin)

Glucocortoid (Dexamethason)

Acepromazine (tranquilizer and pre-anesthetic agent)

Butorphanol (analgesic and pre-anesthetic agent)

Etopside

Mitoxantrone

Ondansetron

Paclitaxel

Rifampicin

 

Class C (used in permitted application form and dose):

Selamectin

Milbemax

Advocate

 

When choosing a veterinarian for your dog, please make sure they are educated on the MDR1 mutation and know which drugs pose a risk to your dog.  You should also keep a list when you are traveling with your dog, because not every veterinarian is aware of these potentially harmful drugs and in some emergency situations time is limited.

15 comments:

  1. Wesa have nevers heard of this, thank you for sharing the information.
    stella rose

    ReplyDelete
  2. Thanks for extensive list. Dad is very weary of Ivermectin and was upset when Interceptor went away. .

    ReplyDelete
  3. This is something I didn't know about, and we have two GSDs. Wow! My vet is pretty savvy, so I'll ask about it the next time we're in.

    ReplyDelete
  4. Good info. It's good to know as much about your breed of dog or the mix of them if possible. Good safety precautions to be made aware of.

    ReplyDelete
  5. Wow we had never heard of this, great post :) Have a super week xxoxxx

    Mollie and Alfie

    ReplyDelete
  6. I never heard of this, so thank you so much for sharing!!

    I do have a question, with the DNA test being so easy and inexpensive, wouldn't it be wise to test the dogs before breeding. In doing so that mutant gene could be bred out.

    ReplyDelete
  7. I couldn't refrain from commenting. Well written!

    ReplyDelete
  8. Good information. Lucky me I came across your blog by accident (stumbleupon).

    I have bookmarked it for later!

    ReplyDelete
  9. Hi there to every single one, it's truly a nice
    for me to go to see this web page, it contains useful Information.

    ReplyDelete
  10. Hi! Do you use Twitter? I'd like to follow you if that would be ok.
    I'm absolutely enjoying your blog and look forward to new posts.

    ReplyDelete
  11. Have you ever considered about including a little bit more than just
    your articles? I mean, what you say is important and everything.
    Nevertheless think of if you added some great graphics or video clips to
    give your posts more, "pop"! Your content is excellent but with pics
    and videos, this blog could certainly be one of the most
    beneficial in its field. Amazing blog!

    ReplyDelete
  12. I'm really loving the theme/design of your blog. Do you ever run into any internet browser compatibility problems?
    A small number of my blog visitors have complained about my website
    not operating correctly in Explorer but looks great
    in Safari. Do you have any recommendations to help fix this
    issue?

    ReplyDelete
  13. I am regular reader, how are you everybody? This paragraph
    posted at this web page is in fact fastidious.

    ReplyDelete
  14. Pretty great post. I simply stumbled upon your weblog and wanted to mention that I have truly loved surfing around your
    blog posts. After all I'll be subscribing for your feed and I
    am hoping you write again soon!

    ReplyDelete
  15. Have you ever thought about creating an e-book or guest authoring on other blogs?
    I have a blog centered on the same information you discuss and would love to have you share some stories/information. I know my subscribers
    would appreciate your work. If you are even remotely interested, feel free to send me an e mail.

    ReplyDelete