Three - parent Englishmen
Great Britain: the first "children of three parents"
Maxim Rousseau, Polit.roo
In the UK, the first permission in the country's history has been issued for the use of donor mitochondria at birth. In the press, this medical technology is often called the birth of a child "from three parents." The general approval of the mitochondrial donation procedure in the UK took place in December 2016, after a long discussion both among scientists and in government bodies.
Recall that mitochondria – cellular organs engaged in the processing of nutrients into ATP molecules – have their own DNA with 37 genes. The child inherits mitochondria from the mother. Some mutations in mitochondrial genes cause severe diseases. Abnormally functioning mitochondria in these cases produce free radicals that damage the cell, disrupt a number of important processes and accelerate cell aging. Mitochondrial diseases are characterized by myopathy, hypotension, low exercise tolerance, cardiac arrhythmias, optic nerve atrophy, disorders of peristalsis and the work of the endocrine glands. The frequency of hereditary diseases associated with mutations in mitochondrial DNA is 1 in 5,000 newborns. Treatment of mitochondrial diseases is currently known only symptomatic, it is impossible to rid the patient of his pathology. In mitochondrial diseases, mitochondria with both normal and defective genomes (the so-called heteroplasmia) are often present in cells, so for some time normal mitochondria satisfy the needs of the body, but sooner or later the number of mutated mitochondria increases so much that they begin to affect the state of health.
Scientists see a way out of this situation in replacing defective mitochondria, which the child should inherit from the mother, with donor ones with a normal genome. Mitochondrial donation uses a woman's egg that does not contain defective mitochondria. In such an egg, a nucleus is transplanted from the egg of another woman who wants to become a mother, but cannot because of mutations in mitochondrial DNA, or who has a high probability that the child will be seriously ill. After that, the egg is fertilized by the sperm of the future father and implanted into the uterus, as with conventional in vitro fertilization.
In 2015, mitochondrial donation was authorized by the UK Parliament, and in 2016 the procedure was approved by the UK Committee on Human Fertility and Embryology (HFEA), which regulates activities in the field of reproductive medicine. In the United States, permission for mitochondrial donation has been blocked by Congress, despite calls from the National Academy of Sciences and the National Academy of Medicine to lift the ban.
Now doctors from the Newcastle Fertility Centre are preparing two women for artificial insemination using donor mitochondria. The HFEA on Thursday confirmed permission for the procedure. Professor of Reproductive Medicine Mary Herbert (Mary Herbert) will lead the work of specialists. The obligation to maintain medical secrecy does not give participants the right to disclose detailed information, but it follows from the orders of the HFEA that both women have a mutation in their mitochondrial genes associated with a dangerous disease known as myoclonic epilepsy with torn muscle fibers, or MERRF syndrome (myoclonic epilepsy with ragged red fibers). MERRF syndrome manifests itself in childhood or in youth. The first sign of the disease is usually myoclonia – involuntary muscle movements. Then the degeneration of muscle tissue increases, damage to the cerebellum begins, which leads to impaired coordination of movements. Convulsions turn into extensive epileptic seizures. There are also atrophy of the optic nerve, deafness, dementia, changes in the heart tissue lead to arrhythmia (Wolf –Parkinson–White syndrome). The disease is steadily progressing, most patients die 20 – 40 years in a state of severe dementia. There is MERRF syndrome in one newborn out of a hundred thousand.
The HFEA reported that after studying the medical history and family history of the patients, it agreed that their children could become victims of a serious illness. Carrying out preimplantation genetic diagnostics, in which embryos are examined before being placed in the uterus and only those that do not have a pathological mutation are selected, was considered useless in this case.
Portal "Eternal youth" http://vechnayamolodost.ru