The babies were conceived via IVF
ZEPHYR/SCIENCE PHOTO LIBRARY
Eight young children have been successfully protected from serious genetic conditions through a groundbreaking procedure that involved using DNA from three individuals. The innovative technique aimed to replace defective mitochondria from the mothers with healthy mitochondria from a female donor.
Approximately 1 in 5000 individuals inherit defective mitochondria, which are responsible for providing cells with energy and are exclusively passed down from mothers. These genetic mutations can result in debilitating conditions such as blindness, seizures, and in severe cases, fatality. Professor Bobby McFarland from Newcastle University describes these conditions as devastating for affected families.
In 2015, the United Kingdom made history by approving a procedure known as pronuclear transfer for women at high risk of transmitting mitochondrial disorders and who would not benefit from traditional preimplantation genetic testing. Pronuclear transfer involves fertilizing eggs from both the mother and a donor with the father’s sperm through in vitro fertilization (IVF). The nuclei, which contain the majority of the genetic material, are then extracted from both eggs after 10 hours. Subsequently, the mother’s nucleus is inserted into the donor’s egg, resulting in an embryo with genetic material from both biological parents and healthy mitochondria from the donor. Despite efforts to minimize the transfer of the mother’s mitochondria, a small amount may inadvertently be passed on, as explained by Professor Bert Smeets from Maastricht University.
Professor McFarland and his team have successfully utilized this technique on 19 women with harmful mitochondrial mutations affecting 80% or more of their mitochondria, a level that typically results in health issues. Seven of these women conceived after the transfer of the modified embryos, giving birth to a total of eight healthy babies, including one set of twins.
Analysis of blood samples from the newborns revealed the absence of harmful mitochondrial DNA mutations in five infants, with only a minimal presence in the remaining three. Professor Mike Murphy from the University of Cambridge commended the results as highly successful.
While all children have been meeting their developmental milestones post-procedure, some have encountered minor complications that may or may not be related to the transfers. For instance, one child experienced elevated blood fat levels and an irregular heartbeat, both of which were successfully treated. Another child developed epilepsy at seven months but spontaneously recovered from the condition.
The research team plans to continue monitoring the children to assess any potential long-term effects of the procedure.
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