News Release

Clinical community crucial in the future of mitochondrial replacement, say experts

Peer-Reviewed Publication

Johns Hopkins Medicine

There is a unique role for the United States medical community to play in determining the future application of, and ethically acceptable approach to, mitochondrial replacement techniques (MRTs), according to a commentary published online by the New England Journal of Medicine.

The United States has a different process for regulating any potential clinical use of MRTs than the United Kingdom, which has also recently addressed policy issues with MRTs, and so the commentary authors emphasize that medical professional organizations, societies, and practitioners will be crucial to determining the ethically acceptable path forward for clinical application of MRTs.

The commentary authors were members of the Institute of Medicine committee which recently released a report commissioned by the Food and Drug Administration (FDA), "Mitochondrial Replacement Techniques: Ethical, Social, and Policy Considerations," and include committee chair Jeffrey Kahn, PhD, MPH, of the Johns Hopkins Berman Institute of Bioethics.

MRTs, which have not yet been performed in humans, are envisioned as a method to prevent a mother from passing on certain debilitating diseases related to mutated mitochondrial DNA (mtDNA). The techniques would replace her mtDNA with that of another woman, while still passing on her own nuclear DNA. Mitochondria are inherited solely from the mother.

"If and when initial investigations are undertaken, critical safety and efficacy questions will remain before regulatory approval or clinical use can occur," the commentary states.

Decisions on how to proceed with initial research uses of MRTs in humans could have a ripple effect for other highly specialized treatments and techniques. "Mitochondrial DNA (mtDNA) disease may the poster child for highly targeted, 'personalized' medicine," the commentary states.

Though MRTs could provide a previously unavailable reproductive option, the authors are careful to note what it cannot achieve. "MRTs would have no health benefits for people who already have mtDNA diseases, nor would they prevent the occurrence of newly arising mtDNA mutations."

"The first use of MRTs in humans is uncharted scientific territory, and requires caution and commitment to the safety of any potential offspring born through use of the techniques," says Kahn, the Levi Professor of Bioethics and Public Policy at the Johns Hopkins Berman Institute of Bioethics. "Any path forward must assess and avoid not only health risks, but take account of psychological effects for the individuals born as a result of these techniques, as well as the social implications of such reproductive technologies."

The authors highlight two key points made in the IOM report: that safety for the individual conceived by the procedure is the primary ethical concern, and that risk to the human germline through heritable changes should be avoided by limiting initial clinical investigations to transfer of male embryos only. This could change, Kahn notes, as knowledge is gained, and depending on the outcome of ongoing international debate about germline genetic modification.


NEJM Perspective, "Mitochondrial Replacement Techniques -- Implications for the Clinical Community":

IOM Report, "Mitochondrial Replacement Techniques: Ethical, Social, and Policy Considerations":

Jeffrey Kahn, PhD, MPH:

Media Contact:

Leah Ramsay

About the Johns Hopkins Berman Institute of Bioethics:

One of the largest bioethics centers in the world, the Johns Hopkins Berman Institute of Bioethics is the home for collaborative scholarship and teaching on the ethics of clinical practice, public health and biomedical science at Johns Hopkins University. Since 1995, the Institute has worked with governmental agencies, nongovernmental and private sector organizations to address and resolve ethical issues. Institute faculty members represent diverse disciplines including medicine, nursing, law, philosophy, public health and the social sciences. More information is available at

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