EIC Testing

Exercise-induced collapse (EIC) is a nervous system disorder that is inherited in Labrador retrievers, Curly coated retrievers, Chesapeake Bay Retrievers, German Wirehaired Pointers, Cocker Spaniels, Boykin Spaniels, Bouvier des Flanders, Old English Sheepdogs and Pembroke Welsh Corgis.

It is inherited as an autosomal recessive trait, meaning that the causative mutation must be inherited from both parents in order to produce an affected puppy.

Carriers of EIC appear normal and have normal exercise tolerance, but they will pass the causative genetic mutation on to half of their puppies. 

Dogs affected by EIC are perfectly normal most of the time and it is impossible for an owner or a veterinarian to determine that there is anything wrong with them. They may, however, experience episodes of collapse when they participate in strenuous activities that they find exciting or stressful, especially in warm weather. 

During a collapse episode, the rear limbs typically become weak and unable to support weight. The dog's gait will become inco-ordinated and they may actually collapse and be unable to move.

Most dogs recover quickly and are not stiff or sore but a few dogs have died. Dogs symptomatic for EIC are rarely able to continue training or competition but they can live normal lives if participation in the types of activities that induce their collapse episodes can be avoided.

Research to investigate and characterize EIC in Labrador retrievers has been led during the last decade by a team at the WCVM (Drs. Taylor and Shmon). They collaborated with a team of veterinarians and geneticists at the University of Minnesota (Patterson, Mickelson, Minor). In 2007,  the genetic mutation causing EIC was identified and a test for the causative mutation was made available through the Veterinary Diagnostic Laboratory at the University of Minnesota.

DNA testing can confirm that a collapsing dog has EIC. More importantly, testing can be used to determine whether a dog that will be used for breeding is:

  • affected by EIC (has two copies of the causative mutation E/E)
  • a carrier of EIC (has one copy of the causative mutation E/N)
  • clear of EIC (no copies of the mutation N/N). 

This is important information to have about a dog prior to breeding so that a breeder can avoid producing dogs affected by EIC.

  • If an affected dog is bred to another affected dog all offspring will be affected.
  • If an affected dog is bred to a carrier dog, 50 per cent of offspring will be affected and 50 per cent will be carriers.
  • If an affected dog is bred to a clear dog, all the offspring will be carriers.
  • If a carrier is bred to a carrier, approximately 25 per cent of the puppies will be clear of the mutation, 50 per cent will be carriers and 25 per cent will be affected by EIC.
  • If a carrier is bred to a non-carrier, none of their pups will be affected, but 50 per cent will be carriers.

Not all dogs affected by EIC (two copies of the mutation) will have had episodes of collapse. Approximately 85 per cent of affected dogs have collapse observed by the time they are three years of age, but some affected dogs never exercise with the intensity and excitement required to induce an episode of collapse.

Without genetic testing it is impossible to say for certain that a dog is not affected by EIC.

The EIC mutation is common in populations of the susceptible breeds. In the populations of dogs tested:

  • 5-15 per cent of Labrador retrievers have been affected, and 35-40 per cent have been carriers
  • 2-3 per cent of Chesapeake Bay retrievers have been affected, and 15-20 per cent have been carriers
  • 15-20 per cent of Curly Coated retrievers have been affected and 30-35 per cent have been carriers.

Testing for EIC involves the collection and submission to the laboratory in Minnesota of an oral swab for DNA. This should be done by a veterinarian. The veterinarian will also verify the identity of the dog being tested (microchip or tattoo) for the laboratory.  

All results are eligible for posting on the Orthopedic Foundation for Animals (OFA) website for a nominal charge with owner consent. For more information about EIC and the test, visit the U of M's Veterinary Diagnostic Laboratory.

Owners who would like to have their dog tested for EIC at the WCVM should do the following:

  • Make an appointment with the Small Animal Medicine service for DNA testing.
  • Go to the EIC website. Click on the submission form option, fill out the form online and print it to bring with them to their appointment.  Filling out the form online minimizes the chance that there will be typographical errors in your dog's information when we submit a handwritten form to the laboratory with the sample.
  • You must pay the Minnesota laboratory directly for the testing (not the WCVM). If you wish to pay for the test by credit card, fill out the credit card authorization form that is attached to the submission form and bring that with you to the appointment.
  • If you do not wish to pay by MasterCard or Visa, you will need to bring a money order or certified cheque for $65.00 US (made out to the Veterinary Diagnostic Laboratory, University of Minnesota) to the appointment so that we can enclose it in the sealed envelope with the sample.
  • Do not give your dog anything to eat or drink (except water) for four hours before your appointment.
  • During the appointment:
    • A veterinarian will collect a history and examine your dog. If your dog is due for routine procedures such as annual examination or vaccination, these can be completed during the same visit.
    • Your dog's permanent identity will be verified (microchip or tattoo) if possible. If your dog has a tattoo please bring a copy of their CKC or AKC registration papers stating the tattoo number for your dog in case one of the letters/numbers is difficult to read.
    • We will perform the DNA swabs, fill out the required forms and seal the samples in envelopes according to directions from the laboratory.
    • We will give you the samples in a sealed, pre-addressed envelope to mail to the laboratory. We recommend mailing the EIC test via ExpressPost (Canada Post) to the Minnesota laboratory.
    • The WCVM Veterinary Medical Centre fee will be the fee for an office call plus a $35.00 DNA collection and processing fee (includes the swabs).