Title:An Update on Non-invasive Approaches for Genetic Testing of the Preimplantation Embryo
Volume: 23
Issue: 5
Author(s): Georgia Kakourou*, Thalia Mamas, Christina Vrettou and Joanne Traeger-Synodinos
Affiliation:
- Laboratory of Medical Genetics, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital,
11527, Athens, Greece
Keywords:
Preimplantation genetic testing, embryo biopsy, cell-free DNA, embryo culture medium, blastocoel fluid, noninvasive PGT, blastocyst.
Abstract: Preimplantation Genetic Testing (PGT) aims to reduce the chance of an affected pregnancy
or improve success in an assisted reproduction cycle. Since the first established pregnancies in 1990,
methodological approaches have greatly evolved, combined with significant advances in the embryological
laboratory. The application of preimplantation testing has expanded, while the accuracy and
reliability of monogenic and chromosomal analysis have improved. The procedure traditionally employs
an invasive approach to assess the nucleic acid content of embryos. All biopsy procedures require
high technical skill, and costly equipment, and may impact both the accuracy of genetic testing
and embryo viability. To overcome these limitations, many researchers have focused on the analysis
of cell-free DNA (cfDNA) at the preimplantation stage, sampled either from the blastocoel or embryo
culture media, to determine the genetic status of the embryo non-invasively. Studies have assessed the
origin of cfDNA and its application in non-invasive testing for monogenic disease and chromosomal
aneuploidies. Herein, we discuss the state-of-the-art for modern non-invasive embryonic genetic material
assessment in the context of PGT. The results are difficult to integrate due to numerous methodological
differences between the studies, while further work is required to assess the suitability of
cfDNA analysis for clinical application.