Preimplantation Genetic Testing Overview

Principles

Definition

Preimplantation genetic testing is a diagnostic methodology employed within assisted reproductive technology that involves analyzing the genetic material of embryos conceived in vitro prior to uterine transfer. This approach investigates chromosomal aneuploidies and monogenic disorders, aiming to identify embryos free from specific genetic conditions to enhance implantation success and prevent the transmission of inherited diseases.

Ontological type

Laboratory Techniques

Clinical Indications

Accuracy and Outcomes

Key developments

Key Figures

Single-Cell Diagnostics era

Edith Coonen [1] was affiliated with Maastricht University [3] as preimplantation single-cell diagnostic work emerged. Her key contributions included identifying the sex of human preimplantation embryos in two hours using an improved spreading method and fluorescent in-situ hybridization with directly labelled probes [6], and optimal preparation of preimplantation embryo interphase nuclei for analysis by fluorescence in-situ hybridization [7], advances that underpinned reliable single-cell genotyping and embryo-level selection. Alan H. Handyside [2] was affiliated with University College London [4] and King's College London [5] during this period. His contributions included articulating the current status of preimplantation diagnosis [8] and reporting clinical experience with preimplantation genetic diagnosis of cystic fibrosis (ΔF508) [9], moves that helped translate single-cell diagnostics into clinical embryo selection.

Genome-wide Chromosomal Screening era

Joep Geraedts [1] was active during this era across Maastricht University [3] and the Universidade de Caxias do Sul [4], shaping early genome-wide chromosomal screening. His key contributions included coordinating and shaping guidelines and data collection for clinical PGD and PGS through the ESHRE PGD Consortium, as reflected in the Best practice guidelines for clinical preimplantation genetic diagnosis (PGD) and screening (PGS) [7], the Data Collection III report [8], and the 2010 What next for preimplantation genetic screening (PGS)? A position statement from the ESHRE PGD Consortium steering committee [9], collectively standardizing practice and accelerating adoption of array-based aneuploidy screening in this era. S. Munné [2] held roles at Cornell University [5] and Yale University [6] during this era, contributing to the translational trajectory of PGD/PGS. Her key contributions included pivotal clinical studies on preimplantation genetic diagnosis of aneuploidy, such as Improved implantation after preimplantation genetic diagnosis of aneuploidy [10], Preimplantation genetic diagnosis reduces pregnancy loss in women aged 35 years and older with a history of recurrent miscarriages [11], and First clinical application of comparative genomic hybridization and polar body testing for preimplantation genetic diagnosis of aneuploidy [12], collectively driving the shift toward CGH/array-based PGS and routine chromosome-level decision-making.

Noninvasive Sequencing PGT-A era

Alan H. Handyside [1] is a pioneer with affiliations at Indiana University Bloomington [3] and the University of Leeds [4] during this era. Handyside [1] co-authored the multicenter randomized clinical trial Preimplantation genetic testing for aneuploidy versus morphology as selection criteria for single frozen-thawed embryo transfer in good-prognosis patients: a multicenter randomized clinical trial [7], illustrating how genetic screening can inform embryo selection and shaping practice in the noninvasive sequencing era. Robert F. Casper [2] is associated with the University of Toronto [5] and Tel Aviv University [6] during this era. Casper [2] co-authored the same paper Preimplantation genetic testing for aneuploidy versus morphology as selection criteria for single frozen-thawed embryo transfer in good-prognosis patients: a multicenter randomized clinical trial [7], contributing to the evidence base guiding embryo prioritization in the noninvasive sequencing era.