Published on
ADVERTISEMENT
Scientists in the UK have successfully given birth to eight healthy babies using a novel technique that combines DNA from three different individuals to prevent the passing on of rare but often fatal genetic diseases. This development, possible due to a 2016 amendment in British law, represents a breakthrough in fertility treatment, though it remains restricted in the United States and many other countries, except for Australia.
Dr. Zev Williams, Director of Columbia University Fertility Centre, remarked that this marks a significant advancement in the field, expanding choices for couples aiming for healthy pregnancies.
Understanding the threat of mitochondrial diseases
While most DNA originates from the cell nucleus and is inherited from both parents, a small portion is found in the mitochondria and only from the mother. Mutations in this mitochondrial DNA can result in severe and generally incurable conditions in children, including seizures, muscle weakness, organ failure, and early death.
Although screening embryos during IVF can sometimes identify these mutations, uncertainty persists regarding rare cases. This has led to the development of a groundbreaking approach: replacing defective mitochondria with healthy ones from a donor egg.
The mother’s genetic material is then inserted into a donor egg that had its nucleus removed, but kept its mitochondria intact. This results in an embryo containing DNA from three individuals: the mother, the father, and the mitochondrial donor.
Breakthrough study and its outcomes
A study conducted by Newcastle University in the UK and Monash University in Australia, published in the New England Journal of Medicine, reports that eight healthy babies have been born to 22 women using this technique. One woman is still pregnant. Although one baby showed slightly elevated levels of abnormal mitochondria, these levels are not high enough to cause disease, and ongoing monitoring is planned.
Dr. Andy Greenfield, a reproductive health expert at the University of Oxford, hailed the work as “a triumph of scientific innovation” to be used when embryo testing is ineffective.
Highlighting the debate, the amount of donor DNA involved is minimal, less than 1 percent of the child’s genome. Stem cell expert Robin Lovell-Badge noted that a bone marrow transplant from a donor would involve significantly more foreign DNA.
Currently, 35 families in the UK have been approved to use the technique, under strict regulation. Concerns about the long-term effects of heritable genetic changes have led the US to prohibit such research, with the FDA unable to consider applications for embryo alterations of this kind.
For families affected by mitochondrial diseases, this technique offers new hope. Liz Curtis, whose daughter Lily died of a mitochondrial disease in 2006, founded the Lily Foundation to raise awareness and support research, expressing excitement for families who now have hope where there was none.
