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Mitochondrial replacement techniques (MRT) are designed to prevent the transmission of mitochondrial DNA (mtDNA) diseases from mother to child. These diseases vary in presentation and severity, but common symptoms include developmental delays, seizures, weakness and fatigue, muscle weakness, vision loss, and heart problems, leading to morbidity and in some cases premature death. The goal of MRT is to prevent the transmission of these serious diseases by creating an embryo with nuclear DNA (nDNA) from the intended mother and mtDNA from a woman with nonpathogenic mtDNA through modification of either an oocyte (egg) or zygote (fertilized egg). Two techniques were considered by the committee – maternal spindle transfer (MST) which involves manipulation of oocytes and pronuclear transfer (PNT) which involves manipulation of zygotes. If effective, MRT could satisfy the desire of women seeking to have a genetically related child without the risk of passing on mtDNA disease, yet the techniques raise ethical, social, and policy issues.
At the request of the U.S. Food and Drug Administration, the Institute of Medicine (IOM) of the National Academies of Sciences, Engineering, and Medicine recently assembled an expert committee to consider the ethical, social, and policy issues raised by the techniques and to address the foundational question of whether it is ethically permissible for clinical investigations of MRT to proceed. The final report, Mitochondrial Replacement Techniques: Ethical, Social, and Policy Considerations, provides an ethical analysis of ethical, social, and policy issues surrounding MRT. While significant ethical, social, and policy considerations are associated with MRT, the most germane of these issues can be avoided through limitations on the use of MRT or are blunted by meaningful differences between the heritable genetic modification introduced by MRT and heritable genetic modification of nDNA. Therefore, the committee concluded that it is ethically permissible to conduct clinical investigations of MRT. To ensure that clinical investigations of MRT were performed ethically, however, certain conditions and principles would need to govern the conduct of clinical investigations and potential future implementation of MRT.
The committee will hold a public discussion about this report on Monday, March 21, from 1:30 PM ET to 3:30 PM ET in the Lecture Room of the National Academies of Sciences Building. For more information, click here.