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Survey on Mosaicism in Preimplantation Genetic Screening (PGS): what is your opinion?

 

It is now apparent that mosaicism exists in a material number of embryos as part of the human conception, and some PGS technolgies are now able to detect its presence. This survey is designed to evaluate the extent of mosaicism in PGS clinical practice and to gain insight on the views and practices of the ART community regarding this issue.

 

Background

Aneuploidy is the leading cause of implantation failure, miscarriage and congenital abnormalities in humans. It is for this reason that preimplantation genetic screening (PGS) was introduced into clinical practice. By transferring only chromosomally normal embryos the clinical outcomes of artificial reproduction techniques (ART) could be potentially improved. Initially, PGS has been performed using fluorescence in situ hybridization (FISH) but its efficiency has been questioned in some studies. One reason why FISH was ineffective has been the fact that only a limited number of chromosomes could be analyzed.
Current PGS practice employs comprehensive chromosomal screening of all 24 chromosomes using either array comparative genomic hybridization (aCGH) or, more recently, next-generation sequencing (NGS) in multicellular biopsy samples from the trophectoderm of blastocysts. However, these techniques, particularly NGS, have unveiled the phenomenon of mosaicism - the presence of cell lineages with different chromosomal constitution. The medical and scientific communities are still uncertain how best to deal with this phenomenon. It is thus the purpose of this survey to evaluate the extent of mosaicism in PGS clinical practice and to gain insight on the views and practices of the ART community regarding this issue.

 

Survey results and analysis

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