Exploring the incidence of trophectoderm mosaicism in a population of previously diagnosed embryos

Human embryo mosaicism: did we drop the ball on chromosomal testing?

“…A 2012 study by Shelly et al compared 30 in-house embryo biopsy results using microarray on TE biopsies provided by a commercial laboratory. This revealed 56.7 % complete concordance and 20 % complete discordance, concluding that the extent of mosaicism was relatively high in the embryo population sampled, and that this was a threat to the ability of PGS to correctly classify embryos as normal or abnormal [31] initially diagnosed Babnormal^embryos were retested as normal. All of these results raise considerable concern over the accuracy and reliability of TE testing for PGS with current laboratory practices [29].…”

“…In well-informed patients with lethal aneuploidy/mosaic embryos and no euploid options, transfer of aneuploid or mosaic embryos may be warranted. This view is based upon the present literature, suggesting that a diagnosis of an aneuploid/ mosaic Babnormal^embryo is not always correct, or if it is correct, mosaicism detected at the blastocyst stage may not manifest as such in a live born [29][30][31]. While testing methodology is able to identify definitely normal and grossly abnormal chromosome complements in most cases, there is a significant, not well-delineated, gray zone into which many chromosome-screening results fall, mostly attributable to the problem of mosaicism.…”