The technique used brings hope, but also concern

The birth of the first child conceived with the help of a new experimental technique that allowed inheriting DNA from three “parents”, two women and a man, in order to avoid the transmission of a serious illness, raises hopes, but also ethical and scientific questions.

This fertilization technique aims to eliminate or minimize mitochondrial abnormalities that are the cause of serious diseases that affect the muscles, eyes, brain or heart, as shown by AFP.

Transmitted exclusively maternally, mitochondria are the “plants” of energy located inside cells. They have a much smaller DNA (only 37 genes) than that of the cell nucleus (23,000 genes).

For little Abrahim Hassan, born of three “parents” and born in Mexico, this procedure was intended to avoid the transmission of a rare disease, Leigh syndrome, which causes neurological degeneration. His mother lost two more children to the disease.

Two similar techniques have been approved in the UK, one started from the embryo, the other from the egg, but so far no authorization has been issued. Dr. John Zhang’s New York team, which made the birth of Abrahim possible, was forced to cross the border into Mexico because there is no legislation in that country.

The researchers used the maternal nucleus transfer technique. This involves taking the nucleus from the future mother’s egg, which is likely to transmit abnormal mitochondria, and transferring it to the healthy egg from a donor. The egg thus obtained will carry the genetic material of two women. Then, it is fertilized with the father’s semen and placed in the mother’s uterus, as happens in a conventional in vitro fertilization. Eventually, the child inherits DNA from two women and a man – but the donor’s contribution is minor, the source said.

This method represents “a new hope” for families affected by these devastating diseases, according to genetics professor Darren Griffin (UK), who speaks of “a new era of preimplantation genetics”.

However, the method is not perfect, as originally thought, draws the attention of David Clancy of the University of Lancaster, because there is a risk of still transmitting a small part of the mitochondrial DNA from the mother.

According to other critical voices, this birth for the first time was not the subject of a detailed article in a renowned scientific journal. Such an occurrence would have allowed the possibility to answer rigorously important questions, among others, regarding the exact percentage of residual maternal mitochondria (carriers of the disease) that the child inherited, however.

According to Dr. Zhang’s team, “less than 1% of the boy’s mitochondria carry the abnormality.”

Other scientists question the Jordanian couple’s long-term monitoring of the child, saying the technique is “risky” and has “unforeseen consequences” on the health of the child and his offspring, as warned by Marcy Darnovsky, director of the Center for Genetics and Society, a California-based NGO.

According to the American Society of Reproductive Medicine (ASRM), Dr. Zhang’s team obtained five embryos, only one of which was normal, the one that became Abrahim.

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