New babies born free of devastating genetic diseases using DNA from three people

SBS Australia

3 days ago

"Lily was my third daughter. She was born five weeks early, small, but otherwise healthy. Around about seven weeks old, she started to have these absent seizures where she would stop breathing and just sort of stare into space. And then we had the situation where she had two cardiac arrests. And she was rushed into intensive care and put on a life support machine." She's reflecting on her daughter Lily, who was born with a rare genetic condition. Doctors struggled to find answers, and further tests eventually confirmed a life-limiting condition with no treatment: mitochondrial disease. Robin Lovell-Badge is the Head of Stem Cell Biology and Developmental Genetics at The Francis Crick Institute. "Mitochondria are these little energy-producing factories, if you like, which all our cells contain. They have their own DNA, and if that DNA carries a mutation, or is a pathogenic variant, it can cause a whole range of different types of disease according to specific mutation, but these are all a nasty set of diseases where children can suffer a lot and die. It's particularly important for energy-demanding tissues like brain and muscle." Lily's family ultimately brought her home after the doctors told them there was nothing more they could do. And for six precious months, she defied expectations. "And I guess it was during those six months that we really started to understand what mitochondrial disease was, what the implications of it were." Over the ocean from the UK lives Ash Greenhalgh, a 28 year old woman from Brisbane who has Leber Hereditary Optic Neuropathy disease, which affects her vision. Her younger brother also has it, as does her mother. "Leading on from my vision loss when I was a child and kind of growing into my teenage years... it was an illness and a disorder with my eyes that was not visible to the people around me. It was internal, which made it very difficult for people to support me and understand. A lot of the times I would hear things like 'won't glasses fix that', which is not the way it works with LHON." Ash says she was overcome upon hearing that scientists at Britain's Newcastle University and Australia's Monash University have pioneered a treatment aimed at preventing such genetic diseases in children. "I cried. I cried. Obviously it's not something that's happening any time soon, but it means the world... I have a lot of gratitude for Monash, I have a lot of gratitude for the researchers who have put in so many countless hours into the research into doing what was the right thing, and helping the community. Because it is genuinely going to make a lot of difference for a lot of people." The idea behind the technique is to produce children who are born free of devastating genetic diseases, including mitochondrial disease, which is passed down through the mother's line. Robin Lovell-Badge says the method uses DNA from three people - the mother's egg, the father's sperm, and a donor's mitochondria - transferring pieces from inside the mother's fertilised egg into a healthy egg provided by the anonymous donor. "What's happened in this case is that they've used a technique called pronuclear transfer which effectively replaces the bad mitochondria with good mitochondria. You actually swap the nuclear genetic material, rather than move the mitochondria around, but you have a donor egg where you remove the nucleus and you replace it with the nucleus from the patient embryo."