Mitochondrial diseases, rare, but formidable, affect approximately one in 5,000. These hereditary disorders, transmitted exclusively by the mother, lead to cellular energy failures that can affect the heart, the brain or the muscles, often from the first weeks of life. Faced with the absence of curative treatments, British researchers have explored an unprecedented preventive solution: mitochondrial donation. This in vitro fertilization process is to replace defective mitochondrial DNA with that of a donor to prevent the transmission of mutations.
Pioneer treatment to break the cycle of hereditary diseases
Mitochondrial diseases leave a devastating imprint on affected families. Transmitted exclusively by mothers, these pathologies are due to anomalies in the DNA of mitochondria. These are the intracellular structures responsible for providing energy to cells. The slightest failure disrupts energy -gourmet organs such as brain, heart or muscles. In some newborns, this results in motor disorders, early blindness, heart failures, even rapid death after birth. “” In some lines, this condemns several generations to live in the fear of losing a child “Recalls Professor Bobby McFarland, specialist in mitochondrial diseases in Newcastle.
It is to break this transmission that researchers have developed a radically different in vitro fertilization technique. The process consists in extracting the nucleus from the fertilized oocyte of the mother – which contains the majority of genes determining the hereditary features – and in inserting it into a donor ovocyte previously emptied of its own nucleus, but endowed with healthy mitochondria. The embryo thus reconstructed keeps the nuclear DNA of both parents and benefits from a mitochondrial DNA exempt from mutations. This fraction, representing less than 0.1 % of the genetic heritage, nevertheless plays a key role in cellular health. “” This offers a unique opportunity to stop the transmission chain of a genetic burden “, Underlines Mary Herbert, member of the research team between Newcastle and the Monash University. The intervention, although complex, wants to be a hope for couples hitherto without solution.
Eight births and encouraging results
The program leads to the Newcastle Fertility Center made it possible to accompany 22 women carrying mitochondrial mutations in an unprecedented reproduction course. On this group, eight were able to give birth to children free from pathologies. These births concern four girls and four boys, including a pair of twins. An additional pregnancy is still in progress, specify the authors in Live science. The first children born thanks to this method today have between five months and two years. All reach the stages of physical and cognitive development expected for their age.
© Monash University and Mitohope
In vitro procedure with 3 DNA.
Attentive medical surveillance implemented has only noted minor problems unrelated to the technique. An infant presented a quickly treated urinary tract infection, another of the temporary muscular contractions, and a third a metabolic disorder successfully corrected. “” These events remain in the usual variability of the first years of life “Specifies Professor Robert McFarland.
The genetic tests carried out after birth provide crucial data. In five cases, no detectable trace of mutated maternal mitochondria was observed. In the other three, residual rates of 5 % to 20 % have been measured in certain tissues. These are well below the 80 % threshold associated with the appearance of symptoms. “” This confirms that the technique considerably reduces the risk of transmission. Even if zero risk does not exist “Comments Professor Mary Herbert. Medical teams provide long -term follow -up. It will include a neurodevelopmental assessment at five years, in order to detect possible late anomalies and further refine this procedure.
A long scientific and legislative path
The emergence of the mitochondrial donation results from a scientific work started more than thirty years ago. In the 1980s, pioneer experiences on mice demonstrated that it was possible to transfer cell nuclees to bypass genetic anomalies. These tests laid the theoretical bases. But the first concrete applications in humans remained decades apart. From the 2000s, British researchers from Newcastle Fertility Center and Newcastle University began to improve technique on non -viable human embryos given to research.
The United Kingdom quickly distinguished itself by its political will to supervise these emerging practices. After a long process of public consultations and sometimes heated parliamentary debates, Human Fertilization and Embryology Authority (HFEA) obtained authorization to regulate this method in 2015. This decision made the country the first in the world to legalize an intervention which modifies the transmitted genetic inheritance. “” Without this clear and rigorous legislative environment, we could never have proposed this treatment to families “, Underlines Doug Turnbull.
In 2017, the NHS joined the mitochondrial donation into a specialized service for rare mitochondrial diseases. This offered unique care to the couples concerned. It is estimated that between 20 and 30 British families could benefit from this technique each year. Outside the United Kingdom, only a few countries follow the same path. Australia adopted similar legislation in 2022. On the other hand, in the United States, the Food and Drug Administration maintains a strict prohibition. She invokes ethical and scientific uncertainties around these germ changes.
Hopes and questions for the future
For families affected by mitochondrial diseases, this technique represents much more than medical progress. They consider it a real deliverance. After years of false layers, lost children and dead end diagnoses, some parents finally see the possibility of having a healthy child. “” After so much uncertainty, this treatment gave us hope, then our baby », Testifies a mother via the Newcastle Fertility Center. Another speaks of “immense lifted weight” and a “gratitude impossible to express”, reports The Guardian.
But if the emotion is lively, caution remains in order. Researchers recall that this method does not guarantee total elimination of mutated mitochondria. In some cases, a low percentage has been detected, without clinical effect at this stage. “” It is a significant reduction in risk, but not absolute protection “, Underlines Mary Herbert at the Bbc. Added to this are persistent ethical concerns. Edit the transmitted genetic heritage questions the border between medicine and eugenics. Some fear a shift to “tailor -made babies”.
Despite these debates, the United Kingdom is positioning itself as a pioneer of a reproductive medicine which is no longer content to accompany births. But it is a medicine intervening upstream to prevent incurable diseases. This turn could inspire other countries to reassess their policies. For the time being, children's medical follow -up remains crucial. “” Seeing these eight healthy children is the most beautiful reward after years of effort and controversy Summates Professor Doug Turnbull. The Mitochondrial gift opens an unprecedented field: that of a controlled genetic transmission, where science tries to interrupt the cycle of hereditary diseases without crossing the ethical limits.
With an unwavering passion for local news, Christopher leads our editorial team with integrity and dedication. With over 20 years’ experience, he is the backbone of Wouldsayso, ensuring that we stay true to our mission to inform.
