MOSCOW, May 13, Nikolay Guryanov. The first children «from three parents» were born in the UK. This method of manifestation into the world avoids the inheritance of severe genetic diseases. What are the disadvantages of innovative technology and why is it not used in Russia?The egg contains tiny organelles — mitochondria, which, among other things, perform the function of the «energy station» of the oocyte. They have their own DNA, and dangerous mutations can accumulate in it. This is fraught with blindness, heart and liver problems, and other serious illnesses.
To solve the problem, Shukhrat Mitalipov, an American biologist of Kazakh origin, and colleagues developed and successfully tested the technology of mitochondrial transfer in animals. A nucleus is removed from a fertilized mother's germ cell and implanted into a donor egg with healthy mitochondria.
In 2015, a team led by American physician John Zhang tested this method on humans. A couple from Jordan couldn't have children due to Leigh's syndrome. This defect, transmitted through the female line, affects the brain. Two children have already died. Moreover, the woman herself was healthy.
The operation was carried out in Mexico, since such procedures were prohibited in the United States. In the spring of 2016, a child from «three parents» was born. It is believed that this is the first case in history. True, there is information that earlier this was illegally experimented with in China and Ukraine. crop-ratio=»0.6072″ data-crop-width=»600″ data-crop-height=»364″ data-source-sid=»rian_infographics» class=»lazyload» lazy=»1″ />
In 2015, in vitro fertilization (IVF) using genetic material from three parents was allowed in Britain. According to The Guardian, since then «about five» babies with donor mitochondria have been born there.
The popular name poorly reflects the essence of the procedure, says geneticist, doctor-expert at the Hemotest Laboratory Irina Kolesnikova.
“In practice, the embryo receives only 37 donor genes, while from the father and mother he gets 20 thousand each,” the expert says. “Thus, it is difficult to fully call the donor a parent: the child will not inherit from him either eye color the shape of the nose, nor the features of the character.»
«Delicate mechanisms are poorly known»
The method is still far from perfect. «During the nuclear transfer, defective mitochondria can still get into the donor egg. In addition, there are too few qualified specialists capable of performing such an operation, and the cost of reagents and equipment is incredibly high,» Kolesnikova explains.
Andrey Glotov, Doctor of Biological Sciences, Head of the Department of Genomic Medicine at the D.O. Ott Research Institute of Agri-Regional Medicine, RSF grantee, scientists do not yet fully understand the possible risks not only of mitochondrial transfer, but also of reproductive technologies in general.
«We are poorly aware of the subtle mechanisms of regulation of donor genetic material already directly in the cell, in the human embryo. We are talking about epigenomic regulation, for example, at the level of DNA methylation, changes in gene expression. This is all the more unpredictable when we are dealing with three genomes,» he says.
At the same time, the scientist argues, on one side of the scale is the health of a particular child who can be saved from a severe hereditary disease, and on the other, insufficiently calculated risks. And at the moment, according to doctors, the first cup outweighs.
«Subtle mechanisms» are being studied. So, Glotov and his colleagues are focused on how sperm, eggs and embryos are affected by freezing, which is indispensable in IVF.
«It is important for us to understand how the storage of biological material, primarily germ cells, will affect health future generations,» he says. «Perhaps the quality of life of children born through IVF depends on how we freeze, thaw and use these materials.»
Three parents — this is not for Russia
Apart from the UK, IVF is legal in Greece and Ukraine. As for Russia, back in 2016, after reports of John Zhang's success, the then Minister of Health, Veronika Skvortsova, said that domestic medicine has all these technologies. However, she doubted their necessity.
«This is not a medical question, it is an ethical one. And it goes beyond the medical sphere. All these issues should be decided by society,» said Skvortsova.
There was a discussion in parliamentary circles — the birth of children from three parents had both supporters and ardent opponents.
Today, doctors believe that IVF is unlikely to become available in Russia in the coming years.
«This procedure is very expensive, it requires special equipment. And most importantly, after all, IVF is still a scientific experiment that has not been confirmed by wide clinical practice,» says Alexander Lapshikhin, a reproductive specialist at the Remedi clinic.
Approximately one in six thousands of children suffer from mitochondrial disorders, points out The Guardian. However, this does not mean that all carriers of such genetic defects will necessarily get sick — some inherit only a small part of the mutated cellular «batteries».
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At the same time, mitochondrial transfer is far from the only way to cope with such pathologies. “For example, now scientists are experimenting with transplanting healthy mitochondria not into an egg, but into the cells of an already born child,” Kolesnikova adds. However, according to her, the scientific community still has a lot of questions about these procedures, so their use is limited.