Jump to content
BC Boards

The Current State of Testing for EAOD


Recommended Posts

Thank you for posting the ABCA HEF statement on EAOD, Eileen, and we all hope that Dr. Lohi and Dr. Mickelson will be successful in identifying the exact mutation soon.  Thank you, for the information about the currently available tests, as well.  

As someone who has a dog with a family history of EAOD (her dam and two littermates lost their hearing at an early age), I chose to have my dog DNA tested by Genoscoper.  It was determined that she is "At Risk".  After I received her DNA test results, I had her BAER tested, and she has been found to have Normal hearing at five years and 8 months of age.  My dog, with her family history and DNA and BAER test results, is of great interest to Dr. Lohi for the ongoing research.  I realize that the currently available DNA tests are not definitive tests for EAOD, but testing our dogs may serve to help provide beneficial information to be used toward discovering the causal mutation.  

Link to post
Share on other sites

I am surprised by a statement that agrees that dogs found clear of the linked genes will not go deaf, which implies you could safely breed those dogs to the carriers and at risk dogs and never produce an affected puppy, and yet the ABCA basically just shot this test down by not supporting it.  With such a high carrier rate we can't afford to eliminate all these dogs from the gene pool, as your statement said.  Nor can we safely keep them in the gene pool without the test.  Every single one of my bitches tested as a carrier.  I had ONE dog come back clear.  I know others in the same boat.  How in the world can we safely proceed with a bloodline unless we utilize testing?  How in the world can we find safe stud dogs to put to our bitches unless people test?

Link to post
Share on other sites
1 hour ago, Liz P said:

I am surprised by a statement that agrees that dogs found clear of the linked genes will not go deaf, which implies you could safely breed those dogs to the carriers and at risk dogs and never produce an affected puppy, and yet the ABCA basically just shot this test down by not supporting it. 

When you say "shot this test down," it sounds as if you think that we somehow prevented it from being offered, or prevented people from using it.  That is certainly not not the case.  The test is still there and anyone can choose to use it.  Our statement is intended to make sure that people recognize the limitations of the test -- that they do not drift into assuming that the results mean more than they do.

1 hour ago, Liz P said:

 With such a high carrier rate we can't afford to eliminate all these dogs from the gene pool, as your statement said.  Nor can we safely keep them in the gene pool without the test.  Every single one of my bitches tested as a carrier.  I had ONE dog come back clear.  I know others in the same boat.  How in the world can we safely proceed with a bloodline unless we utilize testing?  How in the world can we find safe stud dogs to put to our bitches unless people test?

It seems to me that this is an example of someone putting more faith in the test than it merits.  You are assuming that the carrier results are definitive -- that they really mean the dog is a carrier of the EAOD causal mutation.  That's exactly why we felt obligated to set forth our reservations about the test.  In a test that directly tests for the causal mutation, a carrier result means that the dog is actually carrying the causal mutation.   Here in this marker test, the term "carrier" is really a misnomer.  It does NOT necessarily mean the dog is carrying the causal mutation, which is what we were trying to explain.  DO NOT LOSE SIGHT OF THAT FACT.  (For one explanation of why this is so, see the attached scenario, which is an internal working document the HEF used in the course of developing our statement.)

There are some situations where one might feel a need to use the test in its present form.  We mention some of them in the statement.  Another instance where the current test would be useful is if you are buying a pup or about to start training a dog -- a "Carrier" result for that dog would give pretty good assurance that the dog would not lose its hearing early, because it has at least one Clear set of markers.  But for the many people who do not have to make those kinds of decisions immediately, waiting to see if a test for the mutation itself is forthcoming makes all kinds of sense.  

 

                          

   

 

EAOD marker test - One Possible Explanation.docx

Link to post
Share on other sites

"The ABCA HEF does not endorse this marker test, nor do we encourage people to test at this time, before the causative mutation is found."  <--- this line right here

So what are you saying I should do in the case of my bitches, who are all carriers?  Ignore the test results and breed to any stud?  What would I tell those puppy buyers if their dogs go deaf?  That I chose to ignore the results of the best testing option we had at the time?

My plan was to breed the carrier bitches, but only to dogs that tested clear.  According to the ABCA statement, those clear dogs have zero risk.  That is the safest choice for me right now to save a bloodline.  The problem I am having is that many stud owners already decided before the announcement that they would not bother testing.  Now more have said that they won't bother.  My options were just reduced even further.  You want to save genetics?  Encourage testing.

I get it.  The test is not perfect, but I don't ever want to break my heart again, or the heart of a puppy buyer.  I don't want to breed a suspected carrier to a suspected carrier and have to worry that some day those pups might go deaf.  I want to know that at least one parent of the litter has tested clear (and per the committee's very statements, the clears are genuinely clear).
 

Link to post
Share on other sites
On 9/27/2019 at 11:40 PM, Liz P said:

"The ABCA HEF does not endorse this marker test, nor do we encourage people to test at this time, before the causative mutation is found."  <--- this line right here

Here's the full paragraph, from which you quote one sentence: 

 The ABCA HEF does not endorse this marker test, nor do we encourage people to test at this time, before the causative mutation is found. But at the same time, we are not telling people not to test. The test does have some significant benefits, especially for someone whose dogs have deafness somewhere in their pedigree and who must make a breeding decision in the immediate future or who is considering buying or beginning the training of a young dog with deafness in its pedigree. The presence of deafness in a pedigree greatly increases the chances that the marker set will be associated with a causative mutation. The decision whether to purchase the test at this stage is yours alone, but in making that decision here are some factors we think you should consider.  [Emphasis added]

On 9/27/2019 at 11:40 PM, Liz P said:


So what are you saying I should do in the case of my bitches, who are all carriers?  Ignore the test results and breed to any stud?  What would I tell those puppy buyers if their dogs go deaf?  That I chose to ignore the results of the best testing option we had at the time?

I don't know, Liz.  Do you have to breed all of your bitches within the next year?  I'm not familiar with them, so I don't know how urgent the need is.  If you feel that you do, then yes, find a stud who tests Clear, while of course giving at least as much consideration to the dog's suitability as a cross with your bitches.

On 9/27/2019 at 11:40 PM, Liz P said:


My plan was to breed the carrier bitches, but only to dogs that tested clear.  According to the ABCA statement, those clear dogs have zero risk.  That is the safest choice for me right now to save a bloodline.  The problem I am having is that many stud owners already decided before the announcement that they would not bother testing.  Now more have said that they won't bother.  My options were just reduced even further.  You want to save genetics?  Encourage testing.

ABCA and HEF have always encouraged utilization of tests for deleterious genetic mutations, as well as supporting the research aimed at producing those tests.  But we cannot encourage wholesale testing with this marker test -- it would be irresponsible.  The cause of genetic testing would not be advanced if we urged people to use a test that was later found to have given flawed results regarding their dogs.   

I wish the EAOD research we've sponsored had succeeded in identifying the causal mutation, as it appeared for a time it had, but ultimately it has not yet done so.  We are trying to give full information about the test, and to strike a balance between the competing considerations that are implicated here.  Each person must make his/her own decision about testing, including the stud owners you refer to.

Also, it's important to keep in mind that, while breeding carriers to clears is often a good strategy in the short run because it ensures that the offspring will not be affected, it will not work indefinitely in a case where the deleterious gene is carried by a large percentage of the population, because its effect is to increase the percentage of carriers in the population over time.    

Link to post
Share on other sites

I sure hope so — the researchers are working intensively on this from several different directions and are optimistic — but I’ve learned that you never know with science.  If so, it will have been well worth waiting.  But in any case,  we will be issuing another statement within a year, reporting where we are at that point, and reassessing the best ways to proceed in light of that.

Link to post
Share on other sites

I've already spayed one bitch as she is turning 11 soon.  I've kept 2 pups off her.  One is clear and the other a carrier.  The carrier is a bitch and turns 4 soon.  I wanted to breed her to keep a pup.  I've delayed breeding her up to this point because I suspected she might be a carrier.  My other bitch is younger, but at least I have a clear stud to breed to her.

It was 10 years ago that I discussed the DNA test with Dr. Neff.  It's taken this long to get a linkage test released.  

My worry Eileen is that people have read that one line in the statement and already decided to not test based on it.  If what the researchers say it true, the clears are truly clear, then we can use the test currently available.  The issue is finding people willing to test so those of us with carriers can find mates.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...