A $15 million federal government grant is calling for applications from clinics to run a pilot and clinical trial of mitochondrial donation techniques before it can be offered to affected families.
Mitochondrial donation combines the DNA from the eggs of two different women and the genetic material of more than two people: the mother, father and egg donor. The gene combinations created would be inherited by subsequent generations.
One mitochondrial donation technique involves removing the nucleus of a mother’s egg from the surrounding gelatinous cytoplasm that contains unhealthy mitochondria and inserting the nucleus into a donor egg with healthy mitochondria that has had its nucleus removed.
“If you think about a chicken’s egg, the egg white is there to help the chicken grow, similar to the cytoplasm of a human egg, and the yellow egg yolk is like the nucleus that contains the genetic DNA of all those traits that parents pass onto their offspring, like eye and hair colour,” Mills said.
The UK was the first country to legally offer mitochondrial donation to patients in 2017.
Bethany Hodge discovered she was a carrier of mitochondrial disease when her younger sister Annaliese was diagnosed aged 18 after years of unexplained muscle tremors, poor balance and speech difficulties.
“I’ve always dreamed of having a baby that had a part of me in them,” Hodge, 29, said. “But that is not something I want my child – and their future children – to face.”
What is mitochondrial disease?
Mitochondrial disease is a group 300 different disorders caused by mutations in the mitochondria – structures in the gelatinous fluid that surrounds the nucleus of each cell.
These mitochondria are essential for converting the energy from the sugars, fats and proteins in food to the energy that powers the body’s cells.
Between one in 5000 and one in 10,000 Australians are estimated to develop severe or life-threatening mitochondrial DNA disease during their lifetime.
About 50 babies are born with a life-threatening form of mitochondrial disease each year, and many die before the age of five.
The inherited disorder can severely affect entire families, causing organ failure, blindness, deafness, brain disorders and muscular problems. There are no effective treatments.
Hodge and her partner James Frost see mitochondrial donation as their best chance of conceiving a child who carries both their genetic make-up. Boosting egg donations would bring them a step closer to this goal, she said. “It would help so many families break this vicious cycle.”
One of the challenges for mitochondrial donation research is an acute shortage of donated eggs, Mills said.
Demand for donor eggs – both for would-be parents and researchers – significantly outstrips supply, national data shows.
Meanwhile, the number of women freezing their eggs has risen dramatically.
In 2019, women underwent 3395 egg freezing cycles, almost triple the number of cycles just four years earlier, the Australian and New Zealand Assisted Reproductive Database shows.
Almost 5000 women in Victoria alone had eggs in storage on June 30, 2021, up 23 per cent compared to a year earlier, data from the Victorian Assisted Reproductive Treatment Authority shows.
It is too early to know how many of these women will return to use their eggs, though one small study from the UK estimates fewer than 20 per cent do so.
Mills likens her proposal to opt-out organ donation programs overseas, where being an organ donor is the default from birth, unless individuals opt-out. “Women wanting to freeze their eggs would be counselled about their options from the very beginning and will always have the choice to opt-out at any time.”
She said the change would require a broadening of national guidelines regarding egg donation for research purposes, a change to consent and counselling, and potentially the establishment of a national gamete bank, where sperm and eggs would be available for a range of ethically approved research projects.
Chief executive of support and awareness organisation Mito Foundation Sean Murray said having access to donated eggs would be crucial for the pilot program to go ahead.
“It’s important that women are involved in these discussions, which will undoubtedly raise questions for them, and it would be fabulous if they were made aware of the potential benefits of donating eggs to research,” he said.
”My hope for my family and for all people affected by mitochondrial disease is that they have available to them the choice to use mitochondrial donation to avoid transmitting mitochondrial diseases to the next generation,” Murray said.