Preimplantation genetic diagnosis (PGD) and genetic testing for aneuploidy (PGT-A): status and future challenges

Abstract

The world's first in vitro fertilization (IVF) baby was born in July 1978 in the UK. Since then, more than 7 million infants have been born worldwide as a result of IVF. Preimplantation genetic diagnosis (PGD) was introduced in the late 1980s for couples at risk of transmitting a genetic abnormality to their children. From the mid-1990s, this technology has been employed as an embryo selection tool for patients undergoing IVF and has been known as preimplantation genetic screening (PGS). The aim of this practice has been to identify and select euploid embryos for transfer, in order to increase efficacy of IVF cycle, ensure higher implantation rates or at least decreased time to pregnancy. In the early days, fluorescent in situ hybridization (FISH) technology was used for genetic analysis. New advancements in both biopsy and cytogenetic have made possible the improvement of PGD and PGT-A analysis. Currently, a variety of technologies have been implemented to individuate euploid embryos to be preferentially transferred in IVF treatments. The purpose of this review is to clarify the differences between PGD and PGT-A, and to discuss current indications and requirements for embryo biopsy and genetic methodologies used.

摘要

世界上第一例体外受精（IVF）婴儿于1978年在英国出生。此后, 世界上超过700万婴儿经IVF出生。植入前遗传学诊断（PGD）于20世纪80年代末被引入, 用于有可能将异常基因遗传给子女的父母。从20世纪90年代中期开始, 这项技术被应用为进行体外受精的患者的胚胎选择工具并被称为植入前遗传学筛选(PGS)。这一技术的目的是识别和选择用于移植的整倍体胚胎, 提高IVF周期的效率, 确保更高的着床率或至少缩短妊娠时间。早期, 用荧光原位杂交(FISH)技术进行基因分析。活检和细胞遗传学的新进展使PGD和PGT-A分析的进步成为可能。目前, 已有多种技术用于整倍体胚胎的分离, 以便在体外受精中优先转移。本综述的目的是阐明PGD和PGT-A之间的区别, 并讨论胚胎活检的适应证和要求以及所用到的遗传方法学。

The Chinese abstracts are translated by Prof. Dr. Xiangyan Ruan and her team: Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing 100026, China.

Keywords:

• Preimplantation genetic diagnosis (PGD)
• preimplantation genetic testing for aneuploidy (PGT-A)
• cleavage stage embryo biopsy
• blastocyst biopsy

Disclosure statement

The authors have no conflicts of interest relevant to this article.