Eight babies were born in the UK using genetic material from three people to prevent devastating and often fatal conditions, doctors say. The method, initiated by British researchers, consists in combining egg and sperm from the mother and biological father, along with a second egg from a donor.
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According to the BBC, the technique has been legal in the UK for a decade, but it has now been shown to be born in children without incurable mitochondrial diseases.
These conditions are normally transmitted from mother to child, depriving the body of energy.
This can cause severe disabilities, and some children die a few days after birth. Couples know that they are at risk if previous children, family members or mother have been affected.
The children born by the technique of the three people inherit most of their DNA, the genetic imprint, from parents, but they also receive a small amount, about 0.1%, from the second woman. This is a change that is transmitted from one generation to another.
None of the families who have gone through this process speak publicly, to protect their private life, but have issued anonymous statements through the Newcastle fertility center, where the procedures took place.
“After years of uncertainty, this treatment gave us hope-and then gave us our child. Now we look at them, full of life and possibilities, and we are overwhelmed with gratitude“Said the mother of a little girl.
Mitochondria are tiny structures present in almost all our cells. They are the reason why we breathe, because it uses oxygen to turn food into the energy form that our body uses as fuel.
Also, defective mitochondria can leave the body without enough energy to maintain heartbeat and cause brain injury, convulsions, blindness, muscle weakness and organic insufficiency.
About one in 5,000 children are born with mitochondrial disease. The Newcastle team estimates that there is a demand for 20 to 30 children born by the three people’s method.
Some parents have faced the agony of having more children who died from these diseases. Mitochondria are transmitted only from mother to child. Therefore, this revolutionary fertility technique uses both parents and a woman who donates her healthy mitochondria.
The technique was developed more than a decade ago at Newcastle University and at the NHS hospitals in Newcastle Upon Tyne, and in 2017 a specialized NHS service was opened.
The eggs of the mother and donor are fertilized in the laboratory with the sperm of the father.
The embryos develop until the Sperm DNA and the egg form a pair of structures called pronoula. They contain the plans for the construction of the human body, such as hair color and height.
The pronuclei are removed from both embryos, and the parents of the parents are inserted into the embryo full of healthy mitochondria. The resulting child is genetically related to his parents, but should be protected from mitochondrial diseases.
Two reports published in the New England Journal of Medicine have shown that 22 families have gone through this process at the Newcastle fertility center.
He led to the birth of four boys and four girls, including a pair of twins, and a pregnancy.
“To see the relief and joy on the faces of the parents of these children after such a long wait and the fear of consequences, it is great to see these live children, prospering and developing normally“, Prof. Bobby McFarland, the director of the High Specialization Service for Rare Mitochondrial Disorders, told BBC.
All children were born without mitochondrial diseases and reached the expected development stages.
A case of epilepsy has healed by itself
There has been a case of epilepsy, which has healed by itself, and a child has an abnormal heart rate, which is successfully treated.
It is not known whether they are related to defective mitochondria, nor if this is part of the known risks of the IVF, if it is something specific to the three -person method or if it has been detected just because the health of all children born through this technique is intensely monitored.
Another key question that is planning on this approach is whether the defective mitochondria were transferred to the healthy embryo and what the consequences could be.
The results show that, in five cases, the sick mitochondria were undetectable. In the other three cases, between 5% and 20% of the mitochondria were defective in blood and urine samples.
This percentage is below the level of 80% considered to be the cause of the disease. Further research will be needed to understand why this has happened and if it can be prevented.
Prof. Mary Herbert, Newcastle University and Monash University, said: “The discoveries offer reasons for optimism. However, research to better understand the limits of mitochondrial donation technologies will be essential to further improve the results of the treatment. ”
