MIR and Jamie - question about Mosaicism

MIR and Jamie - question about Mosaicism

Joined: August 4th, 2011, 8:18 pm

June 26th, 2012, 7:43 pm #1

Do you know anything about mosaicism? Apparently it is when a cell is tested and shows up abnormal but then corrects itself in the process of growing and dividing? I heard it could be on the order of about 30% so that means that even if the embryo tested abnormal, about 30% of the time it could be normal. I think this might only happen with PGD embryos but not sure. In this case, it seems like even if you test abnormal, you may still want to transfer these, right?

MIR, in your post below, you mention lower pregnancy rates for PGD embryos. Is this because these embryos arrest before day 5? If they make it to blast and test normal, are there still reduced pregnancy rates? When you say reduced, do you mean that they have a lower rate of implantation than an untested blast?

Also, MIR, do you have an email - I have some questions about the surrogacy process.
Last edited by alima1 on June 26th, 2012, 8:48 pm, edited 1 time in total.
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Joined: June 25th, 2012, 2:35 am

June 26th, 2012, 9:45 pm #2

These are great questions, I wonder them myself..I was rechecking my CGH (depressing) report and trying to figure out if there were any more of them that I maybe could have transferred and taken a chance--they were all pretty 'ugly" (multiple trisomies in each) except for the lone monosomy.

This whole thing is interesting, I wish I understood it more...
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Jamie
Jamie

June 26th, 2012, 10:09 pm #3

Do you know anything about mosaicism? Apparently it is when a cell is tested and shows up abnormal but then corrects itself in the process of growing and dividing? I heard it could be on the order of about 30% so that means that even if the embryo tested abnormal, about 30% of the time it could be normal. I think this might only happen with PGD embryos but not sure. In this case, it seems like even if you test abnormal, you may still want to transfer these, right?

MIR, in your post below, you mention lower pregnancy rates for PGD embryos. Is this because these embryos arrest before day 5? If they make it to blast and test normal, are there still reduced pregnancy rates? When you say reduced, do you mean that they have a lower rate of implantation than an untested blast?

Also, MIR, do you have an email - I have some questions about the surrogacy process.
For exactly the reasons you mention. You could have a bad cell causing you to discard a good embryo. MIR is probably the expert here; I have read that this is controversial and some RE's really don't buy into mosaicism. For a lot of reasons I prefer blast biopsy and fortunately my RE's lab does it. MIR will know a lot more and I'm sure she'll be along soon to share her wisdom.
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Joined: December 20th, 2010, 7:38 pm

June 27th, 2012, 12:59 am #4

Do you know anything about mosaicism? Apparently it is when a cell is tested and shows up abnormal but then corrects itself in the process of growing and dividing? I heard it could be on the order of about 30% so that means that even if the embryo tested abnormal, about 30% of the time it could be normal. I think this might only happen with PGD embryos but not sure. In this case, it seems like even if you test abnormal, you may still want to transfer these, right?

MIR, in your post below, you mention lower pregnancy rates for PGD embryos. Is this because these embryos arrest before day 5? If they make it to blast and test normal, are there still reduced pregnancy rates? When you say reduced, do you mean that they have a lower rate of implantation than an untested blast?

Also, MIR, do you have an email - I have some questions about the surrogacy process.
http://www.ncbi.nlm.nih.gov/pubmed/18829021

http://humrep.oxfordjournals.org/conten ... 3.full.pdf

The number is small, but it tells some story. That's why I don't do 3-day embryo PGS because
1) it hurts the embryo, and
2) it may not be reliable

I prefer to grow blasts instead as a weeding tool, and I understand for our age group, as many as 50% of the blasts can be abnormal, but it is a good bet considering the risk and reward. There are many blast PGS studies and the normal ratio is all over the place, but one thing is for sure, many aneuploid embryos simply cannot advance to blast stage (only ~20% abnormal embryos can become blasts).
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Joined: December 20th, 2010, 7:38 pm

June 27th, 2012, 1:33 am #5

One was my former RE, their office offered PGD and when I inquired about it (in 2009), and she knew I could afford it under insurance, she dissuaded me from doing day 3 8-cell PGD because she had a research proving that PGD hurt implantation rate. I am very thankful for her advice, and it is obviously given without self-interest ($4500 less for her clinic).

Another one is my current RE. His clinic started offering PGS on a small scale since Feb. When I talked to him in March, he advised against it for my age because he said most of aneuploid embryos won't implant, or they will become blighted ovum, only an extremely small percentage will survive beyond 1st trimester and I can take care of that via CVS. Then I kept asking him about his genetic testing service, and he always sounded lukewarm. I do know patients in the early 30s at my clinic that found success after implanting PGS-normal embryos. I tend to think that he is watching out for my back when not pushing genetic testing on me.
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ajc
ajc

June 27th, 2012, 2:28 am #6

For exactly the reasons you mention. You could have a bad cell causing you to discard a good embryo. MIR is probably the expert here; I have read that this is controversial and some RE's really don't buy into mosaicism. For a lot of reasons I prefer blast biopsy and fortunately my RE's lab does it. MIR will know a lot more and I'm sure she'll be along soon to share her wisdom.
My DH and I were talking about this tonight, how we would both be more comfortable with the 5 day testing and wondering if the PGS/CGH day 3 testing I had was more of a problem than the theory that all of my 16 retrieved embryos being bad (for 41, that's not a good ratio!). My doc did suggest maybe going for a bunch more embryos transferred (with my history, it would be impossible to have an octo situation. haha) so maybe put in the top 4-6 and cross my fingers, sans testing...It's really compelling to think about..
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Joined: August 4th, 2011, 8:18 pm

June 27th, 2012, 2:34 am #7

The more I read and think about this - it seems like if you have PGD tested embryos that you may just want to transfer even the abnormal ones that have gone to blast. Or just don't bother to test and transfer whatever embryos go to blast.
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Anonymous
Anonymous

June 27th, 2012, 3:47 pm #8

Definitely thinking about this, too--really compelling. Half of me is mentally signed up for RBA DE and half of me is thinking another OE with some different strategy, like you mentioned. Curious If the doctor has any alternate suggestions, too, but have to wait for this cycle to officially be over to ask

Hope my typing is okay, I'm on my phone!
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