Current quantitative methodologies for preimplantation genetic testing frequently misclassify meiotic aneuploidies as mosaic

This study presents the first direct evidence that a third of embryos reported as mosaic (both low- and high-level mosaic) by NGS-based PGT-A contain meiotic errors, highlighting the potential misclassification of aneuploid embryos as mosaic by current NGS-based PGT-A methods that cannot accurately distinguishing between meiotic and mitotic errors. Single-nucleotide polymorphism genotyping provides essential information for accurately determining the origin of chromosomal abnormalities and should be integrated with NGS-based copy number analysis to enhance diagnostic accuracy. Further studies are needed to refine mosaicism classification and to better understand its true implications in in vitro fertilization treatment.