That's correct. If the dog is affected, both parents must be carriers. If the dog is a carrier, at least one parent is a carrier, but not necessarily both. The gene can skip generations, so two unaffected carriers could have an affected offspring.

I'm wondering if some of the dogs that we think have produced TVD, that in some cases it might be EIC?

(of course, cases that were not verified by echocardiograms, etc.)

I know a breeder that has a dog that was tested affected and the dam was clear(tested) ..So how could that be if you said both parents have to be carriers to produce an affected offspring?? Very confusing

The MN University has said that there have been NO cases like this, so if this is really true, they should know about it....someone is not being honest.

The mutation would have to be there in the dam (at least as a carrier) in order to be passed on to an affected.

I would certainly be interested in knowing if the case you speak of is true or not.

--- --- --- --- --- --- --- --- ---

Replying to:

I know a breeder that has a dog that was tested affected and the dam was clear(tested) ..So how could that be if you said both parents have to be carriers to produce an affected offspring?? Very confusing

Yes, if this is truly the case the test is not what it should be. Please have your breeder friend let UMN know before it goes any further. Also please have your friend post both these dogs results on Labradata as well. IT'S VERY IMPORTANT IF THESE ARE ACTUAL RESULTS!

I recently heard a similar story but one important fact in the story that I heard is that the dam was tested in the research phase with a cheek swab..and it was not clear where that swab was collected. If it was done at a field trial(as many were) how certain can they be that the swabs were not mixed up and was it possible that the dog was on a pro's truck and identity was not verified? In the case that I heard about, I believe the dam was going to be re-tested with proof of identity. I haven't heard the results of that re-testing.
I agree that it is very important that the U of M be made aware of those findings. Of course, they are tracking pedigrees so they should already be aware of the findings.

I would agree. If neither sample was mixed up, and the results are conmfirmed for both dogs (And U Minn should do the retesting at their expense!) then the test may not be reliable. That issue needs to be settled.

Checked out the info on the dam and found out she has NOT been tested. Sorry for posting before I had all the facts in hand.

Well, that explains that. Thanks for having the candor to investigate and post your findings about the dam.