A child, three parents. It might seem science fiction, but it is already a reality. It is a reality that It started a decade agowith the approval in the United Kingdom of a novel technique that allowed Enter genetic information of a third person in a fertilization process In vitro
Eight births. The British team to launch this technique has published the results Obtained from monitoring nine babies born after a fertilization process In vitro. A process with an important peculiarity: the introduction of mitochondrial DNA from a donor.
Mitochondrial diseases. To understand the scope of the new procedure, we have to understand the reason that led to the development of this technique, avoid the transmission of mitochondrial DNA diseases. A problem that is estimated affects about 5,000 births per year.
The mitochondria is a part of the cell responsible for producing energy but also has a DNA segment which is inherited matrilinearly. This matrilinear transmission can only be inherited by the mother, although they can affect people of any sex.
This DNA can present harmful mutations that usually affect the proper functioning of this intracellular “energy” central “, which derives in diseases that manifest especially in those tissues that require the most energy, such as those of the heart or the brain. We do not have a cure for these diseases, but now we have a way to cut its transmission.
Pronuclear transfer. The technique It is called pronuclear transfer And, according to the team that has launched it, it is done after the fertilization of the ovule, and consists in transplanting the nuclear genome of the ovule with the mutation to a new donor ovule, this with the desired mitochondrial DNA. The resulting cell has the parents’ nuclear DNA but the mitochondrial DNA of the donor parent.
Studying the technique. The details of the study were described through two articles published in the magazine New England Journal of Medicine. The first of them He focused on studying the success of the technique itself.
The technique did not eliminate the entire original mitochondrial DNA since in the core extraction process, part of this DNA was also captured and introduced into the new cell. According to the team, its presence in the neonate blood ranged between undetectable levels up to 16%.
“The findings give rise to optimism. However, research to better understand the limitations of mitochondrial donation technologies will be essential to improve treatment results,” explained in a press release Mary Herbert, who led this part of the study.
Healthy babies. He Second study He focused on clinical results, both on mothers and babies. During pregnancies only a complication was detected in one of them (hyperlipidemiaan excess of blood lipids), which responded to the prescribed treatment.
The eight babies were born healthy and their development was normal during the study period, with most babies without health problems and the rest with mild problems that the team considers not related to the donation process.
Regarding the success of the process, the team did not detect mitocondrial DNA in five of the eight babies, and the mutations that detected in the remaining three were maintained below 20%, which is far from the limit of 80% from which problems could begin to occur. The monitoring of these cases is still necessary to better know the evolution of each case.
Ethical considerations. This monitoring will be necessary to clear doubts about the possible long -term impacts of this technique, a key consideration in the ethical discussion around the procedure. The United Kingdom approved this technique in 2015, but there are still many countries that have not legislated in this direction.
“The study also raises ethical and scientific questions. The combination of nuclear and mitochondrial DNA of different people could have long -term effects still unknown,” indicated a Science Media Center (SMC) Rocío Núñez Calonge, scientific director of the International UR Group and coordinator of the Ethics Group of the Spanish Fertility Society.
And in Spain? Spain would remain in a legal limbo, without clear legislation in this regard, experts explain.
“In Spain, our (…) (Law) on assisted human reproduction techniques, does not explicitly refer to this technique (which did not exist when this legislation was approved) by what Sensu stricto The procedure would not be expressly prohibited or explicitly authorized in our country. Essentially it is not regulated. The legal and ethical doubts that subsist have prevented, so far, that the technique of the three parents is applied in Spain ”, explained to SMC Lluís Montoliu, researcher at the National Biotechnology Center (CNB-CSIC) and Ciberer -iscii.
Image | Newcastle University / Nathan Dumlao
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