Panel Says FDA Should Approve Experiments on Male ‘Three-Parent’ Embryos
A panel of experts from the Institute of Medicine, a U.S. non-profit advisory organization, recommends that the FDA approve a technique that would create an embryo that has DNA from three parents.
The panel consisted of historians, doctors, bioethicists, and lawyers. Their report says that the FDA should approve so-called “three-parent IVF” for therapeutic purposes — for women who have mitochondrial disease and do not want to pass it on to their offspring.
Mitochondria are the “power houses” of the cell like naturally occurring battery packs. Mitochondria have a small amount of DNA that code for some of the specific things mitochondria do. The other 99.9% of the cell’s DNA is located in the nucleus. While the two types of DNA are in different compartments, they sometimes interact with each other.
When the DNA in mitochondria has a wrong letter in the wrong place, a person has what is called “mitochondrial disease.” There are less than 20,000 cases of mitochondrial disease reported per year in the U.S. Because mitochondria are the cell’s power supply, when something goes wrong, it wreaks havoc on all of the cell’s processes.
The panel approved a technique that takes the nucleus of one woman’s egg and puts it in another woman’s egg cell which contains her mitochondria but not her nuclear DNA. In this way the nuclear DNA is from the mother who has mitochondrial disease and the mitochondrial DNA is from the donor. The modified egg is then fertilized in vitro with the father’s sperm.
Not only did the panel say that using two different women’s DNA should only be used for therapeutic purposes, it also suggested that until scientists know the ramifications of having two different types of DNA in one cell, the technique should only be performed in male embryos. Men do not pass their mitochondria to the next generation. It only comes from the woman’s egg.
As it stands, the FDA cannot approve any clinical trials to create embryos whose genes are from three parents. Part of stipulations in the 2016 federal spending bill is a ban on funding research that involves creating human embryos. If the FDA wants to approve this research, it will have to wait until the next fiscal year.
There are several problems with this technique that are minimized by the veneer of therapeutic benefits and the hype of lascivious headlines like “Three-parent IVF.” The cell operates like a factory with all of the parts working together to do all of the body’s functions. No one really knows what would happen if the parts from one woman could not communicate with the parts from the other woman. A key assumption in approving this technique is that any adverse effects caused by changing the cell’s instruction book (i.e., the nucleus) would be less costly than the benefit of ensuring that the child does not inherit mitochondrial disease.
Additionally, the recommendations from the panel encourage gender selection. Since we don’t know the effects of this technique, particularly the long-term effects that might get passed down to future generations, the panel recommend only performing this technique on male embryos. The only way to do this is either by selecting sperm containing a Y chromosome or making several embryos and destroying the female ones.
The child produced from this technique will be a participant in an experiment that he never consented to. Because mitochondria are so important to cells, he may end up with severe disabilities that may not show up until he is an adult. A report on the committee’s conclusions in Washington Post highlights the lack of concern for the health and well-being of the men born from this technique:
The males-only guideline is intended to prevent the introduction of unwanted, irreversible genetic changes to the human species. Any genetic changes associated with this kind of engineering will meet a dead end in males.
“If there are adverse events, they would not be reverberating down the generations,” Charo said.
The procedure should be extended to female embryos only after the long-term effects of such novel genetic engineering are better understood, the committee concluded.
Finally, contrary to how the issue is being presented in the media, there are other possible solutions to mitochondrial disease. The Los Angeles Times reported on how scientists used induced pluripotent stem cells to replace damaged mitochondria with healthy mitochondria. The lead author of the stem cell study is Shoukhrat Mitalipov, who is also spearheading the US efforts to make embryos from three genetic parents. The stem cell technique, he says, is to help people who already have mitochondrial disease. Mitochondrial replacement would prevent it altogether.
The stem cell approach showed promise because in some cases the patient’s skin cells can be used and their stem cells can be programmed to replace the faulty mitochondria. This solution, which does not have the ethical baggage that making embryos with three genetic parents does, has not gained the same kind of international attention that “three-parent IVF” has even though both are equivalently feasible.
Another, more controversial approach to mitochondrial disease is to use new gene editing technology as a kind of DNA cut-and-paste process. Because this would be done in an embryo, it has ethical issues similar to mitochondrial replacement. And while gene editing is a powerful technique, it sometimes cuts out the wrong portion of DNA.
The UK has already approved the use of mitochondrial replacement therapy in human embryos. The U.S. panel’s recommendation comes on the heels of the UK’s recent approval for scientists to genetically edit human embryos for research purposes.