I recently had some bloodwork done for my 9 year old daughter and decided to have her CPK checked at the same time. It came back normal. I have been tested and am not a carrier. I know my daughters normal CPK means she is most likely not a carrier but that CPK is not conclusive on that and I need to have my girls further checked like I had. My question is, if they come back as not bring carriers are they save to have kids without the risk of DMD? or can they be germline carriers like I may be? Will they have to have the PGD/IVF when they have kids someday?

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So I guess my question is: Why can your eggs DNA (x chromosome) have had a spontaneous mutation while in utero, but not your sons DNA upon fertilization/conception? Unfortunately, I think either scenario can be true....BUT if more of your eggs were mutated and your daughters are carriers, then they are bloodline carriers, not germline and their chance of germline would be the same as any womans....I would think.

Karen Barnett said:
But the genetic counselor told me that the spontaneuos mutation occured while I was in utero and not while with my son in utero. The spontaneous mutation occured with me thus I passed on the mutated X to my son. That to me means that my eggs were effected and I have the germline mosaicism. This is my understanding anyway. There have been some mothers on here that were not carriers, went on to have other children through IVF/PGD and found that a high percentage of their eggs were effected. If this is true than it seems like my daughters would have a higher risk than the general population of having a child with DMD as their eggs could be affected by bad X's through me. Am I thinking along the right lines here?
I was under the impression that if you have at least one egg affected then you are a germline carrier (no matter if you have 1 egg or you have 70% of your eggs, and definitely there is no way to know how many you have affected). A spontaneous mutation would be called if it happened in your son at conception I thought.

But to be honest here, since there is no way to know if it's one or the other, we could all be called germline carriers.


Karen Barnett said:
But the genetic counselor told me that the spontaneuos mutation occured while I was in utero and not while with my son in utero. The spontaneous mutation occured with me thus I passed on the mutated X to my son. That to me means that my eggs were effected and I have the germline mosaicism. This is my understanding anyway. There have been some mothers on here that were not carriers, went on to have other children through IVF/PGD and found that a high percentage of their eggs were effected. If this is true than it seems like my daughters would have a higher risk than the general population of having a child with DMD as their eggs could be affected by bad X's through me. Am I thinking along the right lines here?
agreed. I guess that is a huge part of the problem!!! UGH!!!

Ofelia Marin said:
I was under the impression that if you have at least one egg affected then you are a germline carrier (no matter if you have 1 egg or you have 70% of your eggs, and definitely there is no way to know how many you have affected). A spontaneous mutation would be called if it happened in your son at conception I thought.

But to be honest here, since there is no way to know if it's one or the other, we could all be called germline carriers.


Karen Barnett said:
But the genetic counselor told me that the spontaneuos mutation occured while I was in utero and not while with my son in utero. The spontaneous mutation occured with me thus I passed on the mutated X to my son. That to me means that my eggs were effected and I have the germline mosaicism. This is my understanding anyway. There have been some mothers on here that were not carriers, went on to have other children through IVF/PGD and found that a high percentage of their eggs were effected. If this is true than it seems like my daughters would have a higher risk than the general population of having a child with DMD as their eggs could be affected by bad X's through me. Am I thinking along the right lines here?
I am with Ophelia - I think that all of us who are not true DNA carriers are germline carriers. The question is what percentage of our eggs are affected.

I don't think that DMD is something that happens after conception. If you think about it, if the mutation happens after the cells start dividing, then only 50% or fewer of the cells would carry the mutation - a different kind of mosaicism, and one that I have heard of in Downs Syndrome. But for the boys, if 50% or fewer of cells are affected, you would think that they would be producing some dystrophin, and would be less symptomatic than a true duchenne boy. I'm not a scientist, so this is just hypothesis, but I believe that DMD is present in the eggs before conception.

Karen - everyone is absolutely right. If they are not carriers, your daughters have no more risk of having a child with DMD than the general population. Think of all of the healthy boys out there in the world. For me, everything regarding health is scary and stressful now, but this is one worry that you can put down.

Vicky - dr. josephson, or whatever his name is, needs to be written up by whomever his authorities are. You absolutely need to report him to whatever medical board is in charge of overseeing geneticists. It is unforgivable that he put your daughter at risk of having a boy with duchenne due to false information when that is a decision that is hers alone. His obligation as a doctor is to arm her with all of the information so that she can make an informed choice about her reproductive options. THIS MAKES ME SO MAD! Please do follow up so that he doesn't do the same thing to another family. If you daughter wants to talk about the IVF/PGD process, I am happy to go over our experience with her. We have a one year old healthy son from the process.

Take care,
Mindy
Ofelia,

I am copying this from a booklet that a received from PPMD several years ago.

A mutation inherited from a parent who possessed the mutation, even if it is not expressed in the parent is called a familial mutation. However, it is also possible the mutation occurs only in the afflicted individual (or in the ovum or sperm that created that person), in which case the new mutation is said to be spontaneous.

Mindy,

It also talks about what you mentioned. It says sporadic cases of dmd occur not only during gametogenesis - the production of ova and sperm - but also early in development, during a period called embryogenesis. It may be that only some of a boy's cells carry a defective dystrophin gene, but not all of them. In other words, some of his cells may express the gene and produce dystrophin, even if many of his cells do not. This would lead to a sort of patchwork - like phenotype which geneticists refer to as a mosaic.

Janine
Janine - that's really interesting. I wonder if possibly that's one of the reasons that some boys with DMD are able to walk longer, because they have some cells producing dystrophin? I wonder how they even know that's the case - how do they even track that kind of thing in terms of when the mutation happened?
I remember watching some program several years ago; 20/20 or something like it. It was a case where they were testing the DNA of a young adult for something and then testing his parents. I dont remember why, but they noted several cases like this...
Anyway, the mothers of the 2 boys that I remember were told that there was NO WAY they could be these boys biological mother; the DNA didn't match! Both mothers showed photos of them pregnant, birth certificates, etc....
As it turned out, these women had 2 sets of DNA in them!!! I don't recall the details, but it was very weird and obviously very rare, but depending on the DNA test, they truly had 2 sets!
My sons DNA has been tested 3 times! I am pretty sure he only has one set and they all show DMD!...but it is an interesting scenario!

Mindy said:
Janine - that's really interesting. I wonder if possibly that's one of the reasons that some boys with DMD are able to walk longer, because they have some cells producing dystrophin? I wonder how they even know that's the case - how do they even track that kind of thing in terms of when the mutation happened?
I have posted this link before but thought I would add it here.

http://www.mda.org/Publications/Quest/q81ss.html

Also, Karen don't assume that your daughers normal CPK level most likely means she is not a carrier. Over the years of coming to this board and talking with other carriers I would say that I have run into just as many whose level was elevated as those whose level was not. I am a carrier my level is normal.

Janine

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