Yes, I thought about mentioning mosaicism but it’s such a can of worms with so much debate in the PGT research field that I just left it out.
My reading of the research suggests that mosaicism is far less common than the average PGT test would suggest. Here’s a well done study from 2021 in which the authors took apart 942 embryos and found the true rate of mosaicism to be 3%.
Most PGT labs diagnose mosaicism at far higher rates: 5-15% at most labs. My impression is this is mostly an artefact of noisy, low-density NGS sequencing technology and/or contaminated samples.
It’s also worth noting that we have a single digit number of examples of “mosaicism” in actual people, which suggests to me that there’s either differential apoptosis of aneuploid cells during embryonic development, or that mosaicism is almost always lethal.
Yes, I thought about mentioning mosaicism but it’s such a can of worms with so much debate in the PGT research field that I just left it out.
My reading of the research suggests that mosaicism is far less common than the average PGT test would suggest. Here’s a well done study from 2021 in which the authors took apart 942 embryos and found the true rate of mosaicism to be 3%.
Most PGT labs diagnose mosaicism at far higher rates: 5-15% at most labs. My impression is this is mostly an artefact of noisy, low-density NGS sequencing technology and/or contaminated samples.
It’s also worth noting that we have a single digit number of examples of “mosaicism” in actual people, which suggests to me that there’s either differential apoptosis of aneuploid cells during embryonic development, or that mosaicism is almost always lethal.