No DNA detected

[nuthinbutpink]

Why does this happen with PGD? Day 3 and day 5 we see it.

[TRL]

Yes very curious.
We had 2 day 5 biopsy with no DNA detected.
Is it worth unfreezing and rebiopsying and freezing again? Is this harmful for the embryo?
The two are expanded blasts frozen on day 5.

[Carole]

Yes very curious.
We had 2 day 5 biopsy with no DNA detected.
Is it worth unfreezing and rebiopsying and freezing again? Is this harmful for the embryo?
The two are expanded blasts frozen on day 5.

No DNA detected can be due to poor sample quality so that DNA was not prepared properly and degraded, or a cell missing a nucleus was selected (so no DNA) or the genetic testing lab made a mistake in processing the sample. I doubt that repeated freezing and thawing and biopsy is beneficial (!) but embryos are surprisingly hardy and there are published reports of pregnancies after repeated freezing, but the cases I am aware of had to do with an earlier stage freeze or thaw, followed by some days of culture (recovery) and then re-freeze. Not sure if repeated freezing is more problematic on day 5 embryos which really are near the end of culture and need to be transferred back without much chance for a recovery culture period. Day 5 embryos might go to day 6 of culture but must be transferred or frozen then. Good Luck! Carole

[TRL]

Thanks Carole!

[nuthinbutpink]

If an embryo continues to grow, is it likely a test or lab issue? Do some cells not contain a nucleus and the embryo can still be healthy? What are the odds if the embryo is still growing on day 5 that the cell contained no nucleus on day 3?

Finally, with a day 5 biopsy where they get multiple cells, would no DNA detected be due to the test at that point if the embryo was a viable blast?

[my4leafclover]

would love to know the answers to these questions....not much info out there.

[Carole]

If an embryo continues to grow, is it likely a test or lab issue?

Are you referring to a negative DNA result? See below.


Do some cells not contain a nucleus and the embryo can still be healthy?

Yes, the cells without the nucleus will die but usually there are enough other cells in the tissue or if it is before differentiation, cells that can take it's place. If more than, say 25% of the cells are dead or dying, that obviously is a bigger problem. Usually 1-2 cells are removed for testing from an 8 cell, and between 4-10 from a blastocyst stage embryo (a group of cells is pulled from the trophectoderm). In either case, the rest of the embryo should happily go forward without these cells.


What are the odds if the embryo is still growing on day 5 that the cell contained no nucleus on day 3? Remember, the cell taken via biopsy for testing (the one removed on day 3) no longer has anything to do with the embryo. It's just bad luck that the cell for testing had no nucleus (sometimes difficult to see at biopsy). The majority of the cells remaining in the embryo need to have nuclei or they can't go forward.

Finally, with a day 5 biopsy where they get multiple cells, would no DNA detected be due to the test at that point if the embryo was a viable blast? It would be less likely that ALL the test cells were without nucleus. More likely, the DNA got degraded in one of the technical steps or shipping.

[Carole]

See answers below.

[Luvmyboys]

Carole,

I was curious, is it odd that our euploid embryos show up as no DNA detected?

We have had 3 normal embryos (2 from cycle 1 and 1 from cycle 2) and 1 from cycle 1 and 1 from cycle 2 were no DNA detected. When, they rebiopsied these were both normal healthy xy embryos. They were both hatching blasts.

I'm trying go figure out why this is occurring with a hatching blast both times.

Thanks!

[Luvmyboys]

These were day 5 HB.

[Carole]

These were day 5 HB.

Hi Luvmyboys,
No DNA detected means that the sample had no DNA. This can happen if the cell is lost along the way or if the DNA is degraded and not detectable. It doesn't necessarily mean the cell didn't have any DNA, though it is possible to pull off a large bleb (a membrane enclosed sac of cytoplasm), that seperated from the main cell, leaving behind the nucleus. In any of these cases, another sample would have to be taken and re-assayed. Best wishes, Carole