Latest news with #genetic diseases
CNA
17-07-2025
- Health
- CNA
Three-person IVF technique spared children from inherited diseases, scientists say
Eight children in the UK have been spared from devastating genetic diseases thanks to a new three-person in vitro fertilization technique, scientists from Newcastle University reported on Wednesday. The technique, which is banned in the United States, transfers pieces from inside the mother's fertilized egg - its nucleus, plus the nucleus of the father's sperm - into a healthy egg provided by an anonymous donor. The procedure prevents the transfer of mutated genes from inside the mother's mitochondria - the cells' energy factories - that could cause incurable and potentially fatal disorders. Mutations in mitochondrial DNA can affect multiple organs, particularly those that require high energy, such as the brain, liver, heart, muscles and kidneys. One of the eight children is now 2 years old, two are between ages 1 and 2, and five are infants. All were healthy at birth, with blood tests showing no or low levels of mitochondrial gene mutations, the scientists reported in the New England Journal of Medicine. All have made normal developmental progress, they said. The results "are the culmination of decades of work," not just on the scientific/technical challenges but also in ethical inquiry, public and patient engagement, law-making, drafting and execution of regulations, and establishing a system for monitoring and caring for the mothers and infants, reproductive medicine specialist Dr. Andy Greenfield of the University of Oxford, who was not involved in the research, said in a statement. The researchers' "treasure trove of data" is likely to be the starting point of new avenues of investigation, Greenfield said. Often during IVF screening procedures, doctors can identify some low-risk eggs with very few mitochondrial gene mutations that are suitable for implantation. But sometimes all of the eggs' mitochondrial DNA carries mutations. In those cases, using the new technique, the UK doctors first fertilize the mother's egg with the father's sperm. Then they remove the fertilized egg's 'pronuclei' – that is, the nuclei of the egg and the sperm, which carry the DNA instructions from both parents for the baby's development, survival and reproduction. Next, they transfer the egg and sperm nuclei into a donated fertilized egg that has had its pronuclei removed. The donor egg will now begin to divide and develop with its healthy mitochondria and the nuclear DNA from the mother's egg and the father's sperm. This process, detailed in a second paper in the journal, 'essentially replaces the faulty mitochondrial DNA (mtDNA) with healthy mtDNA from the donor,' senior researcher Mary Herbert, professor of reproductive biology at Newcastle, said at a press briefing. Blood levels of mtDNA mutations were 95 per cent to 100 per cent lower in six newborns, and 77 per cent to 88 per cent lower in two others, compared to levels of the same variants in their mothers, the researchers reported in a second paper. "These data indicate that pronuclear transfer was effective in reducing transmission of mtDNA disease," they said. The procedure was tested in 22 women whose babies were likely to inherit such genes. In addition to the eight women who delivered the children described in this report, another one of the 22 is currently pregnant. Seven of the eight pregnancies were uneventful; in one case, a pregnant woman had blood tests showing high lipid levels. There have been no miscarriages. The authors of the current reports have also tried transplanting the nucleus of a mother's unfertilized egg into a donor egg and then fertilizing the donor egg afterward, but they believe their new approach may more reliably prevent transmission of the genetic disorders. In 2015, the UK became the first country in the world to legalize research into mitochondrial donation treatment in humans. That same year in the United States, pronuclear transfer was effectively banned for human use by a congressional appropriations bill that prohibited the Food and Drug Administration from using funds to consider the use of "heritable genetic modification".
RNZ News
17-07-2025
- Health
- RNZ News
Eight babies born using DNA of three people cutting genetic disease risk
By Daniel Lawler and Julien Dury , AFP One out of every 5000 births is affected by mitochondrial diseases, which cannot be treated. (File pic) Photo: 123rf Eight healthy babies have been born in the UK using a new IVF technique that successfully reduced their risk of inheriting genetic diseases from their mothers, the results of a world-first trial. The findings were hailed as a breakthrough which raises hopes that women with mutations in their mitochondrial DNA could one day have children without passing debilitating or deadly diseases on to the children. One out of every 5000 births is affected by mitochondrial diseases, which cannot be treated, and include symptoms such as impaired vision, diabetes and muscle wasting. In 2015, Britain became the first country to approve an in-vitro fertilisation (IVF) technique that uses a small amount of healthy mitochondrial DNA from the egg of a donor - along with the mother's egg and father's sperm. Some have called the result of this process "three-parent babies", though researchers have pushed back at this term because only roughly 0.1 percent of the newborn's DNA comes from the donor. The results of the much-awaited UK trial were published in several papers in the New England Journal of Medicine . A lab worker checks the result of an IVF procedure. (File pic) Photo: Out of 22 women to undergo the treatment at the Newcastle Fertility Centre in northeast England, eight babies were born. The four boys and four girls now range from under six months to over two years old. The amount of mutated mitochondrial DNA - which causes disease - was reduced by 95-100 percent in six of the babies, according to the research. For the other two newborns, the amount fell by 77-88 percent, which is below the range that causes disease. This indicates the technique was "effective in reducing transmission" of diseases between mother and child, one of the studies said. The eight children are currently healthy, though one had a disturbance of their heart's rhythm which was successfully treated, the researchers said. Their health will be followed up over the coming years to see if problems arise. Nils-Goran Larsson, a Swedish reproductive expert not involved in the research, hailed the "breakthrough". The new technique offered a "very important reproductive option" for families affected by "devastating" mitochondrial diseases, he added. Mitochondrial donation remains controversial and has not been approved in many countries, including the United States and France. Religious leaders have opposed the procedure because it involves the destruction of human embryos. Other opponents have expressed fears it could pave the way for genetically engineered "designer babies". An ethical review carried out by the UK's independent Nuffield Council on Bioethics was "instrumental" in conducting the new research, the council's director Danielle Hamm said on Wednesday. Peter Thompson, head of the UK's Human Fertilisation and Embryology Authority which approved the procedure, said only people with a "very high risk" of passing on a mitochondrial disease would be eligible for the treatment. Ethical concerns have also been raised over the use of mitochondrial donation for infertility in Greece and Ukraine. French mitochondrial disease specialist Julie Stefann told AFP that "it is a question of the risk-benefit ratio: for a mitochondrial disease, the benefit is obvious". "In the context of infertility, it has not been proven," she added. Oxford University reproductive genetics expert Dagan Wells observed that "some scientists will be a little disappointed that so much time and effort has, so far, only led to the birth of eight children". Among the children being closely monitored are three that showed some signs of what is known as "reversal", which is still little understood. It is "a phenomenon where the therapy initially succeeds in producing an embryo with very few defective mitochondria, but by the time the child is born the proportion of abnormal mitochondria in its cells has significantly increased", he explained. -AFP
