Clinical-grade whole genome sequencing-based haplarithmisis enables all forms of preimplantation genetic testing.

High-throughput sequencing technologies have increasingly led to discovery of disease-causing genetic variants, primarily in postnatal multi-cell DNA samples. However, applying these technologies to preimplantation genetic testing (PGT) in nuclear or mitochondrial DNA from single or few-cells biopsied from in vitro fertilised (IVF) embryos is challenging. PGT aims to select IVF embryos without genetic abnormalities.

Embryo tracking system for high-throughput sequencing-based preimplantation genetic testing.

Study Question: Can the embryo tracking system (ETS) increase safety, efficacy and scalability of massively parallel sequencing-based preimplantation genetic testing (PGT)?

Summary Answer: Applying ETS-PGT, the chance of sample switching is decreased, while scalability and efficacy could easily be increased substantially.

What Is Known Already: Although state-of-the-art sequencing-based PGT methods made a paradigm shift in PGT, they still require labor intensive library preparation steps that makes PGT cost prohibitive and poses risks of human errors. To increase the quality assurance, efficiency, robustness and throughput of the sequencing-based assays, barcoded DNA fragments have been used in several aspects of next-generation sequencing (NGS) approach.

In vitro fertilization does not increase the incidence of de novo copy number alterations in fetal and placental lineages.

Although chromosomal instability (CIN) is a common phenomenon in cleavage-stage embryogenesis following in vitro fertilization (IVF), its rate in naturally conceived human embryos is unknown. CIN leads to mosaic embryos that contain a combination of genetically normal and abnormal cells, and is significantly higher in in vitro-produced preimplantation embryos as compared to in vivo-conceived preimplantation embryos. Even though embryos with CIN-derived complex aneuploidies may arrest between the cleavage and blastocyst stages of embryogenesis, a high number of embryos containing abnormal cells can pass this strong selection barrier.

Multi-centre evaluation of a comprehensive preimplantation genetic test through haplotyping-by-sequencing.

Study Question: Can reduced representation genome sequencing offer an alternative to single nucleotide polymorphism (SNP) arrays as a generic and genome-wide approach for comprehensive preimplantation genetic testing for monogenic disorders (PGT-M), aneuploidy (PGT-A) and structural rearrangements (PGT-SR) in human embryo biopsy samples?

Summary Answer: Reduced representation genome sequencing, with OnePGT, offers a generic, next-generation sequencing-based approach for automated haplotyping and copy-number assessment, both combined or independently, in human single blastomere and trophectoderm samples.

What Is Known Already: Genome-wide haplotyping strategies, such as karyomapping and haplarithmisis, have paved the way for comprehensive PGT, i.e.