Does anyone know which exon or exons would have to be skipped for my grandsons' mutation, which is a duplication of exons 8 thru 11? Where can I find that information?

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I use this webpage: http://www.dmdregistry.org/reports/predictor/

I don't really understand how exon skipping works with duplications, so I can't explain the genetics behind it, but the predictor says: "It is predicted that skipping exon/s 8-11 would restore the reading frame of the gene."

Good luck, Keith
Try Duchenne Connect. Or, you could contact Univ of Utah Genetics Dept. but I would try Vanessa at Duchenne Connect first.
I don't know what the time difference is but Annemieka Aarsma-Russ is doing an online discussion this Sunday (see link below).

http://community.parentprojectmd.org/events/annemieka-aartsmaruss-o...

She may be able to shed some light on the complications associated with excising multiple exon duplications, as they are as not as straight forward as the deletions...

I have attached a copy of one of her latest abstracts for you to have a read of, as it shows the problems associated with restoration of the reading frame when dealing with duplications:

"Abstract Background Antisense-mediated exon skipping is currently one of the most promising therapeutic approaches for Duchenne muscular dystrophy (DMD). Using antisense oligonucleotides (AONs) targeting specific exons the DMD reading frame is restored and partially functional dystrophins are produced. Following proof of concept in cultured muscle cells from patients with various deletions and point mutations, we now focus on single and multiple exon duplications. These mutations are in principle ideal targets for this approach since the specific skipping of duplicated exons would generate original, full-length transcripts. Methods Cultured muscle cells from DMD patients carrying duplications were transfected with AONs targeting the duplicated exons, and the dystrophin RNA and protein were analyzed. Results For two brothers with an exon 44 duplication, skipping was, even at suboptimal transfection conditions, so efficient that both exons 44 were skipped, thus generating, once more, an out-of-frame transcript. In such cases, one may resort to multi-exon skipping to restore the reading frame, as is shown here by inducing skipping of exon 43 and both exons 44. By contrast, in cells from a patient with an exon 45 duplication we were able to induce single exon 45 skipping, which allowed restoration of wild type dystrophin. The correction of a larger duplication (involving exons 52 to 62), by combinations of AONs targeting the outer exons, appeared problematic due to inefficient skipping and mistargeting of original instead of duplicated exons. Conclusion The correction of DMD duplications by exon skipping depends on the specific exons targeted. Its options vary from the ideal one, restoring for the first time the true, wild type dystrophin, to requiring more 'classical' skipping strategies, while the correction of multi-exon deletions may need the design of tailored approaches
Annemieka also reported the very duplication you are enquiring about in a recent report outlining the current situation on exon skipping:

http//www.treat-nmd.eu/userfiles/file/general/Exon%20Skipping%20Report%20...

The entire report is well worth reading as it is very informative and gives a great outline of the process involved in exon skipping. However specific to your request, page 6 reads as follows:

"At the request of a family whose son had the exons
8-11 duplicated, Annemieke answered to explain the difficulties:
“We would need a combination, a cocktail of AOs
targeting all four exons 8-11. But these AOs cannot discriminate
between the original and the duplicated exons.
So the result will be skipping of either the original exon 8,
the duplicated exon 8 or of both exons 8. Or it may skip
the original exon 9, the duplicated exon 9 or both, or a
combination of exons 8 and 9, and so on. Thus there are
many possibilities only one of which – skipping the duplicated
exons 8, 9, 10 and 11, but not the original exons 8, 9,
10 and 11 – will restore the reading frame. The effect is
diluted. Simply increasing the amount of the AOs in the
cocktail will not change the situation. We are trying to find
solutions for these problems but things are not as straightforward
as with deletions. We do not know if, and if so,
when exon skipping will be applicable for large duplications“.

I'm sorry I couldn't offer you a more encouraging answer, however this technology has come along in leaps and bounds in the last decade, and who knows where it will lead us in the future?

Hugs to you and your family,

Jules
So my son has a duplication of 45.. is this saying that exon skipping has been done for this duplication and produced dysrophin
Thank you everyone for your responses. I was also discussing this with Pat. It would seem that exon skipping will probably not work for my grandsons in the near future, if at all. This does upset me because it seems like exon skipping is on the near horizon. But I need to look on the bright side, so I will ask your opinions as to what other research would you deem is on the near horizon that would benefit my grandsons?
research utrophin upregulation, and myostatin. I think they are coming up soon. Maybe sooner than what ever exon skipping cocktail mixture your grandson would require. Yea, these exon skipping cocktail mixtures (for multiple skipping and others) seem way off into the future for our well being.

Terry Porcaro said:
Thank you everyone for your responses. I was also discussing this with Pat. It would seem that exon skipping will probably not work for my grandsons in the near future, if at all. This does upset me because it seems like exon skipping is on the near horizon. But I need to look on the bright side, so I will ask your opinions as to what other research would you deem is on the near horizon that would benefit my grandsons?
Thanks Cheryl. I will now be following the research on utrophin upregulation and myostatin more closely. I appreciate everyone's support.

cheryl cliff said:
research utrophin upregulation, and myostatin. I think they are coming up soon. Maybe sooner than what ever exon skipping cocktail mixture your grandson would require. Yea, these exon skipping cocktail mixtures (for multiple skipping and others) seem way off into the future for our well being.

Terry Porcaro said:
Thank you everyone for your responses. I was also discussing this with Pat. It would seem that exon skipping will probably not work for my grandsons in the near future, if at all. This does upset me because it seems like exon skipping is on the near horizon. But I need to look on the bright side, so I will ask your opinions as to what other research would you deem is on the near horizon that would benefit my grandsons?
Hi Amanda,

How effective each oligo treatment will be in the individual is vary hard to predict, as not all mutations are "neat and complete". However if your son has a single exon duplication at 45, all indications are that he would be suitable as a candidate when 45 is approved.

I am a firm believer in the "nothing ventured, nothing gained" mentality, and this situation would definitely be one where I would consider the treatment, if that is what we felt was best for our son. Worst case scenario is that either both exons 45 are removed, resulting in a nonsense mutation that would then require 44 or 46 to be skipped, or that the wild type exon was removed, and the duplicated exon was an incomplete duplication that still resulted in an out of frame mutation (highly unlikely).

Best case scenario of course is that the duplicated 45 is removed, full length, wild type dystrophin reading frame is restored, and your son's future looks so much brighter as he is not even producing a truncated dystrophin, and therefore, his progression (if any) should be minimal.

I have everything crossed for you Amanda :)

, Amanda Rudd said:
So my son has a duplication of 45.. is this saying that exon skipping has been done for this duplication and produced dysrophin
I can see how complicated it is to come up with the correct cocktail for duplications, but from what you just said, if the correct cocktail could be found, it could be possible to have the full length dystrophin reading restored. If that were the case, it would almost seem like a cure. Is my thinking going a little too far?

Julie Gilmore said:
Hi Amanda,

How effective each oligo treatment will be in the individual is vary hard to predict, as not all mutations are "neat and complete". However if your son has a single exon duplication at 45, all indications are that he would be suitable as a candidate when 45 is approved.

I am a firm believer in the "nothing ventured, nothing gained" mentality, and this situation would definitely be one where I would consider the treatment, if that is what we felt was best for our son. Worst case scenario is that either both exons 45 are removed, resulting in a nonsense mutation that would then require 44 or 46 to be skipped, or that the wild type exon was removed, and the duplicated exon was an incomplete duplication that still resulted in an out of frame mutation (highly unlikely).

Best case scenario of course is that the duplicated 45 is removed, full length, wild type dystrophin reading frame is restored, and your son's future looks so much brighter as he is not even producing a truncated dystrophin, and therefore, his progression (if any) should be minimal.

I have everything crossed for you Amanda :)

, Amanda Rudd said:
So my son has a duplication of 45.. is this saying that exon skipping has been done for this duplication and produced dysrophin
You would get a complete dystrophin produced, however it could never be deemed a cure, as the oligo only targets the mRNA, not the genome, and therefore it's affects are not permanent. Therefore each boy will need continued treatments, and of course as each course nears it's end there will be some loss of protein function, and therefore some deterioration, however it would not be anywhere near as severe as the progression without oligo treatment.......

Not that all hope is lost for boys that will not benefit from exon skipping - utrophin as Cheryl mentioned may offer some solutions, plus they have found a way to deliver a truncated dystrophin protein that is grown in-vitro (they just have to work on systemic uptake), and (if memory serves me right) there is a team working on complete (427kda) dystrophin delivery systems...... we truly are standing at the dawn of a new era when it comes to treatments for Duchenne :)

Terry Porcaro said:
I can see how complicated it is to come up with the correct cocktail for duplications, but from what you just said, if the correct cocktail could be found, it could be possible to have the full length dystrophin reading restored. If that were the case, it would almost seem like a cure. Is my thinking going a little too far?

Julie Gilmore said:
Hi Amanda,

How effective each oligo treatment will be in the individual is vary hard to predict, as not all mutations are "neat and complete". However if your son has a single exon duplication at 45, all indications are that he would be suitable as a candidate when 45 is approved.

I am a firm believer in the "nothing ventured, nothing gained" mentality, and this situation would definitely be one where I would consider the treatment, if that is what we felt was best for our son. Worst case scenario is that either both exons 45 are removed, resulting in a nonsense mutation that would then require 44 or 46 to be skipped, or that the wild type exon was removed, and the duplicated exon was an incomplete duplication that still resulted in an out of frame mutation (highly unlikely).

Best case scenario of course is that the duplicated 45 is removed, full length, wild type dystrophin reading frame is restored, and your son's future looks so much brighter as he is not even producing a truncated dystrophin, and therefore, his progression (if any) should be minimal.

I have everything crossed for you Amanda :)

, Amanda Rudd said:
So my son has a duplication of 45.. is this saying that exon skipping has been done for this duplication and produced dysrophin
Hi Julie,

Could you provide a bit more information as to who is doing the delivery of truncated dystrophin you mentioned?

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