12 April 2017

The health of the "three-parent child" is in danger

The data of the genetic examination of the world's first child from three parents have been published

Marina Astvatsaturyan, Echo of Moscow

When last year it became known that the American private clinic of artificial insemination used to conceive a child born in Mexico was given a controversial method in which genetic material from three people is combined, both ethical and scientific questions immediately arose, addressed to the head of the clinic, Dr. John Zhang.

Months later, while the debate was going on and speculation was being born, Zheng's group provided additional information about the conception of a child in an article published in early April by the journal Reproductive Biomedicine Online (Live birth derived from oocyte spindle transfer to prevent mitochondrial disease).

However, the main questions about the boy's health in the long term remain, and this calls into question the progressiveness of the experiment with triple parenting itself. The method of creating a "child from three parents" is designed to enable mothers with diseases caused by defective mitochondria to have healthy children. Mitochondria are intracellular structures that have their own DNA, the child inherits them from the mother, since the embryo develops from an egg containing mitochondria, like any cell. When donating healthy mitochondria from another woman, you can expect the birth of a healthy child, and this woman will be the third parent.

In the described case, Dr. Zheng and his colleagues at the New Hope Fertility Center clinic in In New York, the nucleus was removed from the egg of a healthy woman and replaced with a nucleus from the egg of a woman - an expectant mother – with a rare neurological disease, Ley syndrome. The resulting egg with donor mitochondria and the mother's nucleus was then fertilized with the father's sperm and then implanted into the mother's uterus. The first child from three parents was born in April 2016.

Dr. Zheng's article provides new details of the procedure concerning the method of transferring the maternal nucleus, but the main thing is that scientists found that a trace amount of defective mitochondrial DNA of the mother got into the donor egg.

Whether this will affect the boy's health in the future is a question. The problem is that in this case there will be no answer to it, because the parents refused to continue monitoring the child's health. The percentage of damaged mitochondria transferred to the boy varies in different tissues.

The content of maternal mtDNA in samples of tissues and biological fluids – VM.

According to Zheng and co–authors, about 2% of the mitochondrial DNA of the cells in his urine are maternal, but in the skin cells of the foreskin analyzed after the circumcision of the boy, this value increases to 9%. Studies in mice have shown that a mixture of healthy and defective mitochondria can lead to neurological or metabolic problems.

Portal "Eternal youth" http://vechnayamolodost.ru  12.04.2017

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