Single-cell multi-omics sequencing reveals chromosome copy number inconsistency between trophectoderm and inner cell mass in human reconstituted embryos after spindle transfer.

This article investigates whether the chromosome copy number of the trophectoderm (TE) in human blastocysts derived from spindle transfer (ST) embryos accurately represents that of the inner cell mass (ICM), using single-cell multi-omics sequencing. The study found that ST blastocysts exhibit a higher proportion of mosaicism and chromosomal copy number variations (CNVs) across a broader range of chromosomes compared to conventional intracytoplasmic sperm injection (ICSI) blastocysts. Importantly, statistical analyses including Bland–Altman and Kappa tests demonstrated good concordance between TE and ICM chromosome copy numbers in ICSI blastocysts, supporting the clinical use of preimplantation genetic testing for aneuploidy (PGT-A) in these embryos. Conversely, TE and ICM in ST blastocysts showed poor concordance, indicating that TE biopsies may not reliably reflect ICM chromosomal status in ST embryos, which raises concerns about the accuracy of PGT-A for ST-derived embryos. The study highlights the need for further research on the unique embryonic biology of ST embryos and cautions against routine clinical application of PGT-A in this context until more data are available.