Mitochondrial replacement seeks to remove genes known to cause genetic defects from embryos in order to allow for a baby to avoid inheriting the defect.
Mitochondrial Replacement Techniques: Ethical, Social, and Policy Considerations from the USA National Academy of Sciences
- limiting clinical investigations to women who are otherwise at risk of transmitting a serious mtDNA disease, where the mutation’s pathogenicity is undisputed, and the clinical presentation of the disease is predicted to be severe, as characterized by early mortality or substantial impairment of basic function; and
- transferring only male embryos for gestation to avoid introducing heritable genetic modification during initial clinical investigations.
Following successful initial investigations of MRT in males, the committee recommends that FDA could consider extending MRT research to include the transfer of female embryos if clear evidence of safety and efficacy from male cohorts, using identical MRT procedures, were available, regardless of how long it took to collect this evidence; preclinical research in animals had shown evidence of intergenerational safety and efficacy; and FDA’s decisions were consistent with the outcomes of public and scientific deliberations to establish a shared framework concerning the acceptability of and moral limits on heritable genetic modification.
The research in this area is interesting and our ability to help achieve healthy lives continues to grow. The path to a bright future though is not without risk. It requires careful action to pursue breakthrough improvements while minimizing the risks we take to achieve better lives for us all.
The findings confirmed the suspicions of many researchers, and the conclusions drawn by Mitalipov and his team were unequivocal: The potential for conflicts between transplanted and original mitochondrial genomes is real, and more sophisticated matching of donor and recipient eggs — pairing mothers whose mitochondria share genetic similarities, for example — is needed to avoid potential tragedies.
“This study shows the potential as well as the risks of gene therapy in the germline,” Mitalipov says. This is especially true of mitochondria, because its genomes are so different than the genomes in the nucleus of cells. Slight variations between mitochondrial genomes, he adds, “turn out to matter a great deal.”