Expanding the horizons of embryo screening: performance and case studies of preimplantation genetic testing via whole genome sequencing

Conventional preimplantation genetic testing for aneuploidy (PGT-A) and for monogenic disorders (PGT-M) is very limited in scope. These methods typically assess chromosomal ploidy or target only one or two specific variants carried by the parents. When the genetic variant is complex, testing often requires DNA samples from additional family members with a confirmed diagnosis, which complicates the process. In some cases, PGT laboratories may even decline testing due to the complexity of the condition. In 2024, we introduced the first PGT—whole genome sequencing (PGT-WGS), enabling the screening of thousands of genes as well as the detection of critical microdeletions and microduplications in one assay. Here, we present assay performance and two clinical case studies illustrate its utility: one showing high concordance between embryo and cord blood of a live-birth child for variants, and another identifying a previously unrecognized monogenic form of diabetes in embryos. These results demonstrate that PGT-WGS expands the clinical utility of preimplantation testing.