Presentation Title: “The ethical issues of PGT-P”

Abstract:

In May 2020, Aurea, the first child produced from an embryo selected via Preimplantation Genetic Testing for Polygenic disorders (PGT-P) was born. Although PGT-P is similar to conventional preimplantation genetic testing (PGT-M, PGT-SR, and PGT-A) in the process of cell collection, diagnosis, and transplantation, it differs in both the method it uses for genetic diagnosis, and the diseases it targets. While conventional preimplantation diagnosis "identifies" a single gene or chromosomal abnormality, PGT-P "represents" the risk of expression of a trait (Polygenic Risk Score: PRS) involving multiple genes in each embryo in a complex manner. Specifically, while conventional preimplantation diagnosis identifies single gene disorders such as Duchenne muscular dystrophy, chromosomal abnormalities such as Down's syndrome (21 trisomy), and chromosomal translocations that cause recurrent miscarriage, PGT-P represents the risk of more common diseases such as type II diabetes, heart disease, and schizophrenia that involve multiple genes and are also associated with environmental factors. For example, Aurea was selected and born with a lower risk than other embryos for future exposure to heart disease, diabetes, cancer, and schizophrenia. Another major difference from conventional preimplantation diagnosis is that it is now technically possible to screen not only for disease but also for non-disease genes associated with characteristics such as height and intelligence. 　With these characteristics, PGT-P is expected to give to rise to new ethical issues in addition to the concerns that have been raised over conventional preimplantation genetic testing. The purpose of this presentation is to present the issues that need to be discussed in PGT-P and the conditions under which PGT-P is acceptable. As for the problem posed by PGT-P, (1) its low clinical utility, (2) the danger that will cause an increased burden in embryo selection, and (3) potential negative effects of the use of the technology on ensuing parent-child relationships are the main candidates. In addition, PGT-P may further reinforce concerns surrounding exacerbating eugenicist tendencies and widening social disparities, losing of genetic diversity, which have also been raised as objections to conventional preimplantation genetic testing. Considering these issues, this presentation will discuss under what conditions PGT-P is acceptable.