Approved since 2015 in the United Kingdom, research on the Mitochondrial Replacement Technology (MRT), presented as a treatment by donation of mitochondria, is being carried out by the Newcastle Fertility Center.
As early as 2018, the British Reproduction and Embryology Authority (HFEA) approved the first in vitro fertilization trials using this technique. It is a process which, while not treating the disease from which the mother is suffering, is not without risk for the child either.
Mitochondria are micro-organelles present in almost all human cells and which generate most of a cell's energy. They are mainly provided by the oocyte during fertilization and are therefore essentially of maternal origin.
Sometimes mitochondria have genetic abnormalities that cause serious and incurable medical conditions. To prevent a mother whose mitochondria are failing from transmitting this anomaly to her child, the mother's mitochondria are replaced with mitochondria from a donor.
Until now, women with defective mitochondria could appeal for egg donation. With the donation of mitochondria, the embryos carry the DNA of the biological father, the DNA of the biological mother and the mitochondrial DNA of the donor (which represents approximately 37 genes).
To date, there is no guarantee that the child thus conceived is actually free from the disease of which its mother is a carrier. Interviewed by The Guardian, genetics professor Dagan Wells of the University of Oxford admits that, while clinical experiences of the mitochondrial transfer technique are encouraging, the number of cases remains too low to be sure of the safety and the effectiveness of the technique.
Mitochondria can indeed remain attached to the nucleus of the egg at the time of nuclear transfer, multiply or even take over compared to healthy mitochondria. This involves selecting in vitro the embryo that will have a rate of abnormal mitochondria of less than 10%, but also verifying the absence of a “turnaround” during pregnancy by means of prenatal tests.
This technique presents two moral transgressions at two different levels. The first is that of in vitro fertilization in general, which is reprehensible for many reasons: the immoral obtaining of male gametes in the first place, and second, all the consequences such as the multiple destruction of embryos which mark the history of this technique.
The second transgression is specific to this technique: from in vitro fertilization to prenatal testing, without forgetting embryonic selection, the technique of mitochondrial transfer is punctuated by manipulations that are currently still uncertain and which question ethics from the point of view of dignity, of the genetic heritage and the health of these children who are the subjects of experimentation.
There are now many works on epigenetics which have shown that the various manipulations that accompany and surround in vitro fertilization are responsible for various genetic diseases. The full list is still being compiled.