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Discussion Starter #1
So, a pup has come down with primary idiopathic megaesophagus. This is a genetic disease which genes are passed by both parents. The breeder that owns the dam has retired her and she will be getting placed into a pet home. This was her first litter. The sire's owner is not acknowledging that their dog carries the Mega E gene and has continued to set up more breedings with this dog. It is the belief that the sire's owner is not telling the bitch's owners that the dog has produced a Mega E pup. This is the sire's second litter.

What would you do?
 

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I would put the pup's pedigree on the PDB and list the megaesophagus issue. That way people researching pedigrees can be aware.
 

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I wouldn't throw the baby out with the bathwater. Like all health issues, it has to be weighed in terms of many other factors. There are also far worse issues that a dog could produce than MegaE. Especially if it is a mild case that the dog outgrows. Severity, frequency of occurrence, and what the dogs have to offer in terms of other temperament and health traits to their pups all need to be taken into consideration.

We had ONE pup in a litter of 9 with MegaE. Jenn's Glory. She outgrew symptoms in puppyhood. No other pups in the litter were affected. Neither sire nor dam was retired due to that one pup. The dam had one more litter with a different sire, 11 pups, no MegaE. So 20 pups total from the dam, only 1 MegaE. The sire has had several other litters to total many dozens of pups, with several different dams, all with no MegaE. Two full sisters and one half sister of the dam have also been bred, producing several other litters between them, with no MegaE in any of those either.

So there would certainly appear to be much more complexity to the inheritence of this disorder than a simple autosomal recessive as some believe. And it's not impossible that as with other similiar disorders, inheritance in one breed isn't the same as in other breeds. Regardless of means of inheritance, people have to keep the total dog in mind as well as overall production record. If every dog is eliminated from breeding if it produces one undesireable trait or pup, even if pretty severe, there won't be many dogs left to breed.
 

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They have actually figured out more on the inheritance portion of ME in regards to GSD's. If a dog actively has ME and is bred, it only takes that one parent. If not, then both the sire and dam have to have the gene to pass it to the pups. So if the dogs are still being bred, they continue to pass the gene on and make more carriers.

Why is it different with ME than it is with hip displaysia? If a dog has severe hip displaysia then the dog would not (or at least should not) be bred. Wouldn't that be considered taking dogs out of the gene pool as well?
 

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Is there published data available about the inheritance of mega-E?

As someone who had a dog with it, and who has raised puppies with it.... it can be a heartbreaking disease.

Chris- At what point did you know Glory had Mega-E?
 

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I don't know alot about mega e on how it's passed. But I see in your first post you said that "BOTH" had to have the gene to pass it on? If this is so, who's to say if bred to a different sire/dam that it would ever happen again??

Is there a 'test' to see if a dog is a meg e carrier? I mean how do they "know" for sure that both dogs are mega e carriers?
 

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Discussion Starter #7
I don't know alot about mega e on how it's passed. But I see in your first post you said that "BOTH" had to have the gene to pass it on? If this is so, who's to say if bred to a different sire/dam that it would ever happen again??

Is there a 'test' to see if a dog is a meg e carrier? I mean how do they "know" for sure that both dogs are mega e carriers?

There is no test yet. Clemson university is currently working on it, but they are still in the early stages.

If there was a test, it would be easy. Carriers breed to clear, no breeding of affected. Too bad it isn't that easy. :(
 

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DM tests are not as accurate as once thought, either.
 

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If I was a breeder, and I had a dog that had produced a Mega-E pup, but was an outstanding dog in every other aspect, I don't know if I would retire him from breeding. But I would certainly be honest and open about the Mega-E issue, and I would hope anyone else in the same situation would be honest and open about it. Otherwise you could be breeding carrier to carrier and never know it! If the guy with the stud dog is lying to people or conveniently failing to mention that his stud has produced Mega-E, I would save him the time and trouble and just make it a matter of public record. :D I think you can enter it into the PDB database.
 

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They have actually figured out more on the inheritance portion of ME in regards to GSD's. If a dog actively has ME and is bred, it only takes that one parent. If not, then both the sire and dam have to have the gene to pass it to the pups. So if the dogs are still being bred, they continue to pass the gene on and make more carriers.


They thought they had inheritance of DM figured out in GSDs too, but there sure seems to be a lot of evidence to the contrary coming out, and I think it would be very detrimental to throw out all the dogs who might have 'bad genes' especially when these DNA marker tests are apparently not as cut and dried as some people think.

And if the tests are accurate, then there is the option of utilizing them to prevent producing dogs who are affected without having to eliminate all carriers from breeding and potentially narrow the gene pool severely in doing so.

Every dog has bad genes and will pass them on. Eliminate every dog without perfect genes from the genepool, and there will be no more dogs. Period. Breeders have to gather as much info as possible and use it judiciously to minimize risk, but no matter how much we all may wish things were different, there is no way to eliminate risk.

It's interesting that there are breeding programs out there that overfocused on specific health problems, and did in fact all but completely eliminate those health problems from their lines, only to have new ones pop up in much greater frequency than exists in the general GSD population. It's always balance, and as the saying goes "when you breed something in, you breed something else out" and vice versa.



Why is it different with ME than it is with hip displaysia? If a dog has severe hip displaysia then the dog would not (or at least should not) be bred. Wouldn't that be considered taking dogs out of the gene pool as well?
It isn't. But originally you were talking about a dog who had produced a pup with MegaE. Now you're talking about a dog who HAS severe dysplasia. That IS different.

The affected dog should not be bred. A dog who is related to the affected dog, even if a littermate or parent, IMO should not automatically be thrown out on that alone. Goodness, if we eliminated every dog who produced or had a littermate with HD from breeding, we really wouldn't have anymore GSDs. The same common sense, look at the big picture approach needs to apply to all traits.

And honestly, one area where MegaE is preferable to other health problems is that it is becomes apparent when pups are very young. Usually as soon as they start solid food. So it should never be a surprise to the new owner. The breeder ought to be able to identify it well before pups are going home, determine the severity and then either euthanize or place the pup in a home appropriately based on that information.
 

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Chris- At what point did you know Glory had Mega-E?
We suspected as soon as she started solid food. We did barium x-rays between 6 and 7 weeks to confirm the diagnosis. She'd pretty much outgrown any symptoms before she went to her new home at 9-10 weeks, but of course technically still has it.

As I said in my previous post, not that any health issue is good, but if you're going to have one health problem or another that is one upside to MegaE over others. With juvenille MegaE, symptoms almost always start to present as soon as the pup starts solid food. Sometimes sooner. So if the breeder is paying attention there shouldn't be any surprise.
 

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Yes, the litter I raised it was obvious from day 1 that something was wrong. They were severely affected. I picked them up, took them to the vet who told me impossible that it was mega-e this young. By 3 weeks we did confirm, but a total of 7 out of 9 puppies died. The two females lived.
 

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I read the articles and don't find where they are saying that they understand the inheritance pattern. The Clemson site says that they think they've identified the chromosome it is carried on, but not much more than that except that they believe it to be "complicated" in GSDs. Which would indicate not a simple recessive or dominant but rather a polygenic disorder like HD and most others. MegaE has been proven to have simple inheritance patterns in some other breeds, recessive in some and dominant in others (so clearly it isn't always the same across breeds), but not in GSDs. But I don't see where they are saying that they know enough about it in GSDs to be assuming anything about carrier status of other related dogs, nor where the statement that if a dog is affected it only takes that one dog to produce a MegaE pup but if not affected it takes 2. That seems contridictory, as the first statement indicates a dominant inheritance pattern, which clearly isn't the case in GSDs, and the second indicates a recessive inheritance. Can't be both unless it is not only polygenic, but also multifactorial.
 

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I also don't believe it is as simple as dominant and recessive genes. I had a pup that had MegaE and out of 10 pups he was the only one that had it. If both the mother and father were carriers in theory 2.5 dogs would've had the disease. I know many of us understand alleles and the punnet square theory, but I don't think all genetics work that easily. If this gene was so simple, that liter would've proved it to be so. I'm not sure how gagsd ended up with so many of the pups with the disease but something else must've been at work there, and not being a geneticist I can't really tell you what it was. The breeders decided to retire my pup's mother (we got another dog from that liter) and our first pup lived to be 1.5 years old and then passed away from complications having to do with the disease. The sire has had 4 liters, and only that one pup has had the disease. 3 liters were with another dam so it makes sense why they didn't have any signs, but in theory they should all be carriers. So imagine the spread of the disease if it was truly that genetically simple.
 

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Discussion Starter #17
Chris, I can't do the quotes like you did so I will try to answer here.

The HD comment was nothing more than an example, not a change of topic. It was meant as one is cut out so why not the other.

My biggest thing is when is enough enough, if that makes sense. It's kinda of like trying to mask the gene through breeding instead of trying to get rid of it. I know I have alot to learn with genetics and pairings for breeding, as well as multiple other things. I am just really trying to get a good grasp on this defect.
 

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Discussion Starter #18
Also, for those of you that pm'd a specific breeder on here thinking I meant them, it IS NOT that breeder. I have already informed them of that.
 

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If it were PROVEN to be autosomal recessive, then yes, the stud owner and bitch owner ought to disclose. However it has not been, to my knowledge.

If a dog has been bred several times with zero incidents, then one affected pup pops up.... I personally would not rule out breeding the parents again. Although probably not to each other.
 

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Discussion Starter #20
I emailed Dr Clark and I hope to hear something back within the next day or 2. I will gladly update when I hear back.
 
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