The U.S. National Academy of Medicine believes that the U.S. Food and Drug Administration (FDA) should approve clinical trials for the transfer of DNA from healthy human eggs to diseased embryos, a divisive gene-therapy technique that will allow the replacement of an embryo's mitochondria with healthy mitochondria from the egg of a second woman, according to Scientific American. While the aim of this procedure is to prevent DNA mutations from stimulating the transmission of diseases, concerns are high regarding the safety of mitochondrial replacement as well as the idea of a child with three genetic parents.
One issue is the potential for problems that could stem from incompatible mitochondrial and nuclear DNA from two different women - numerous experiments on mice, fruit flies and other animals showed that the mixture of these two forms of DNA from individuals with different genetic makeups increases the chances of reduced growth, early death, fast aging and reduced reproductive ability, according to Nature.
Scientists suggest that as of now, the technique should be limited to use only in male embryos as a safety precaution since children inherit mitochondria from their mothers, meaning that male offspring would not be able to pass down their modified and potentially dangerous mitochondria to future generations. However, if this procedure is deemed to be safe after this initial testing phase in male embryos, it may have the potential to be expanded to female embryos.
If the research does move forward, it most definitely won't happen this year. The FDA is carefully reviewing the procedure, although no money will be funneled into reviewing applications that involve inheritable genetic modification of embryos, as per Congress when they passed the FDA's 2016 budget, Medical Xpress reported.
"It is ethically acceptable to go forward, but go slowly and with great caution," said Jeffrey Kahn, a bioethicist at John Hopkins University. "Mitochondrial DNA disease can be extremely devastating, and for the women who are at risk of passing it on to their children, they have no other option by which to pursue having a child that's genetically related to them."
"It's unlikely we'll find any cure once the child is born already with these mutations," said Shoukhrat Mitalipov of Oregon Health & Sciences University. "The best way is to prevent it."
