One hundred mosaic embryos transferred prospectively in a single clinic: exploring when and why they result in healthy pregnancies

Abstract

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A systematic review on concurrent aneuploidy screening and preimplantation genetic testing for hereditary disorders: What is the prevalence of aneuploidy and is there a clinical effect from aneuploidy screening?

“…The few rates of mosaicism reported in the included studies are in line with previous studies, showing that mosaic embryos constitute a small but potentially significant part of the embryo cohort, with potential to produce liveborn offspring . In general, if aneuploidy screening is performed, and there are no euploid embryos available, mosaic embryos could be prioritized based on the chromosome(s) affected by aneuploidy, the type of aneuploidy and the degree of mosaicism detected, preferably according to guidelines provided by the Preimplantation Genetic Diagnosis International Society (PGDIS) and Controversies in Preconception, Preimplantation and Prenatal Diagnosis (COGEN) . In general, each center utilizing PGT‐A should develop evidence‐based guidelines for embryo prioritization to ensure standardization of the treatment and transparency to both patients and piers.…”

Estimating Demand for Germline Genome Editing: An In Vitro Fertilization Clinic Perspective

“…Interestingly, recent data have shown that blastocysts classified by PGT-A as chromosomally mosaic (harboring a mix of euploid and aneuploid cells) can result in implantation and healthy pregnancies, although with significantly lower success rates than blastocysts classified as euploid. [53][54][55] To date, *300 babies born from transferred mosaic embryos have not presented medical complications of any kind. [53][54][55] Evidence from mouse and human embryology indicates that in a mosaic embryo euploid cells dilute out aneuploid cells as the latter preferentially die off or divide at slower rates during development.…”

“…[53][54][55] To date, *300 babies born from transferred mosaic embryos have not presented medical complications of any kind. [53][54][55] Evidence from mouse and human embryology indicates that in a mosaic embryo euploid cells dilute out aneuploid cells as the latter preferentially die off or divide at slower rates during development. 55,56 Deleting an extra chromosome when trisomy is present would typically imply the creation of uniparental disomy, since the GGE machinery would need to target the chromosome that is dissimilar and contains differentiating DNA sequences.…”

Does every family couple that being treated with assisted reproductive technologies need to use preimplantation genetic testing for aneuploidy (PGT-A)?

“…qPCR -є експрес-методом визначення анеуплоїдії. Не визначає незбалансовані транслокації, часткові анеуплоїдії, триплоїдії та мозаїчні ембріони [21,38,42]. Частота помилки 1%.…”

“…Ця думка не безпідставна, тому що є певна кількість вагітностей за яких було проведено імплантацію мозаїчного ембріона, що розвинувся в нормальну вагітність та народження здорових дітей [13]. Причини даного факту з'ясовано в новітніх дослідженнях та визначено, що для настання нормальної вагітності за трансферу мозаїчного ембріона має значення тип мозаїцизму, його кількісна оцінка та вік матері від якої отримані дані ембріони [38].…”