Researchers announced on Wednesday that in Britain, eight healthy babies were born using an experimental technique that involves DNA from three individuals to prevent mothers from passing rare genetic diseases to their children. Most of our genetic material is located in the cell nucleus, inherited from both parents, defining our unique biological makeup. However, there is also DNA in cell structures called mitochondria, and mutations in this mitochondrial DNA can lead to severe diseases in children.
While in vitro fertilization tests can typically identify these mutations, there are cases where this is not possible. To address this, scientists have developed a method that uses healthy mitochondria from a donor egg. This technique involves transferring genetic material from the mother’s egg or embryo into a donor egg or embryo with healthy mitochondria but lacking the key DNA.
Dr. Zev Williams, from Columbia University Fertility Center, described this research as a significant advancement that broadens reproductive options for couples seeking safe and healthy pregnancies. This approach results in embryos with DNA from three individuals – the mother, the father, and the mitochondrial donor – and was approved in the UK via a law change in 2016.
A recent study published in the New England Journal of Medicine detailed the successful application of this technique in 22 patients, resulting in the birth of eight babies without mitochondrial diseases. While one baby exhibited slightly elevated levels of abnormal mitochondria, it is not considered significant enough to cause disease. The procedure, praised by experts as a groundbreaking scientific achievement, is reserved for cases where other methods of preventing genetic diseases are ineffective.
Critics have expressed concerns about the long-term implications of these innovative techniques on future generations. In the UK, couples seeking to use donated mitochondria must be approved by the country’s fertility regulator, with 35 patients currently authorized for the procedure.
“Currently, pronuclear transfer is not allowed for clinical use in the U.S. due to regulatory restrictions on techniques that could lead to heritable changes in embryos,” stated Williams from Columbia in an email. The possibility of a change in this regulation is uncertain and will be influenced by ongoing scientific, ethical, and policy discussions. For nearly a decade, Congress has blocked the Food and Drug Administration from considering applications for clinical research involving techniques that intentionally create or modify human embryos with heritable genetic alterations. However, in countries where this technique is permitted, advocates believe it could offer hope for some families.
Liz Curtis, who lost her daughter Lily to a mitochondrial disease in 2006, now supports other families impacted by these conditions. She expressed the heartbreak of being told there was no treatment for her eight-month-old baby and that her death was unavoidable. The diagnosis completely disrupted their lives, with little information available about the disease or its impact on Lily. Curtis later established the Lily Foundation to raise awareness and fund research into the disease, including recent advancements at Newcastle University. She emphasized the potential of these developments to bring hope to families facing similar challenges.
The report was contributed by Ungar from Erie, Pennsylvania. The Associated Press Health and Science Department is funded by the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation. The AP bears full responsibility for all its content.”
