Can genetic testing be performed on embryos before they are implanted?

From the Guidelines

Yes, genetic testing can be performed on embryos before they are implanted during in vitro fertilization (IVF), a process called preimplantation genetic testing (PGT). This procedure involves removing a few cells from an embryo created through IVF and analyzing them for specific genetic conditions or chromosomal abnormalities before selecting which embryos to transfer to the uterus, as supported by a recent study published in 2024 1. There are different types of PGT: PGT-A screens for abnormal chromosome numbers, PGT-M tests for specific inherited genetic disorders like cystic fibrosis or Huntington's disease, and PGT-SR examines structural rearrangements in chromosomes.

The process of PGT is considered a valuable tool in reducing the risk of inherited diseases, as highlighted in a study published in the Journal of the National Comprehensive Cancer Network 1. However, it's essential to weigh the benefits against the potential risks and costs. The procedure typically adds about $5,000-$10,000 to IVF costs and is not always covered by insurance. PGT can help reduce the risk of having a child with certain genetic disorders and may increase the chances of a successful pregnancy by selecting embryos without chromosomal abnormalities, as noted in the most recent guideline published in Circulation 1.

Some key points to consider when deciding on PGT include:

• The type of genetic disorder or condition being tested for
• The age of the individuals involved
• The potential risks and benefits of the procedure
• The cost and availability of PGT
• Personal and ethical considerations, as discussed in the context of hereditary cancer syndromes 1. It's crucial to consult with a healthcare provider or genetic counselor to determine if PGT is right for your specific situation, considering the latest clinical guideline for preimplantation genetic testing in inherited cardiac diseases 1.

From the Research

Genetic Testing Before Embryo Implantation

• Preimplantation genetic testing (PGT) is a technique used to identify genetic abnormalities in embryos before they are implanted during in vitro fertilization (IVF) cycles 2, 3.
• PGT can screen embryos for chromosomal abnormalities, monogenic disorders, and structural rearrangements, and has undergone significant development over the past few decades 2.
• There are three primary forms of PGT: PGT-A, PGT-M, and PGT-SR, which are used to detect different types of genetic abnormalities 2.

Types of Genetic Testing

• PGT-A is used to screen embryos for aneuploidies, which are abnormalities in the number of chromosomes 2, 4.
• PGT-M is used to detect disorders caused by a single gene, while PGT-SR is used to detect chromosomal abnormalities caused by structural rearrangements in the genome 2.
• Next-generation sequencing (NGS) is a technique that can be used for PGT to identify normal/balanced euploid embryos 5, 6.

Clinical Applications and Outcomes

• PGT can improve clinical outcomes in terms of embryo implantation, clinical pregnancy, and live birth rates 3.
• The use of NGS for PGT has been shown to be effective in identifying normal/balanced euploid embryos, even in cases of complex chromosomal rearrangements 5.
• Studies have compared the reproductive outcomes of different types of structural rearrangements, including reciprocal translocation, inversion, and Robertsonian translocation, and found significant differences in the rates of unbalanced chromosomal abnormalities 6.