Sunday, June 20

Mitochondrial donation: how an IVF procedure could help Australian families “break the gene chain” | Health


My brother Michael was born in April 1998. He didn’t live long enough for me to know him.

“When he was born, he was not getting fat,” my mother tells me. “We continue to persevere in breastfeeding and try formulas. But nothing was working. “

After two months they took him to vaccinate.

“I remember looking at other babies in the waiting room. They were all the same age as him, but much older. It still fit the Bonds romper he wore as a newborn. “

Michael Touma died of a mitochondrial disease before his first birthday
‘There was dread in my stomach. It was a mother’s instinct ‘: Michael Touma died of a mitochondrial disease before his first birthday. Photography: Touma family

That day, my parents took Michael to the pediatrician, who placed them during their lunch break. When Michael showed no signs of joint reflexes, they were told to go straight to the hospital.

“There was dread in my stomach. It was a mother’s instinct: she knew something was wrong, ”she tells me.

Eventually, the genetics team at the hospital diagnosed Michael with a rare form of mitochondrial disease.

“He did so many tests in those months. The needles, the lumbar punctures. It was like a cushion of pins. “

Doctors referred to his illness as a “myth.” My parents had never heard of him before.

“It affected his liver and his muscles. He was tube fed. We had to crush vitamins and put them through the tube with their milk. But he would take out the tube and we had to take him to the hospital in the middle of the night. “

Michael was in and out of the hospital until he died in December of that year.

After Michael’s death, my parents took a lot of risk by deciding to have another child (me).

“If we wanted to have another child, there was a 25% risk that it would happen again. We take a risk with you. And throughout the pregnancy, I was a disaster. “

Nineteen years later, an IVF procedure is close to being legalized in Australia, which would mean that carriers of mitochondria would not have to take that risk to start a family.

What is ‘myth’?

In Australia, about one child a week is born with a severe form of mitochondrial disease. Most young children diagnosed with mitochondria die by age five.

It is a rare genetic disorder that affects the function of our cells’ power plants, our mitochondria, effectively starving the body’s cells of energy.

Professor John Christodoulou, chairman of genomic medicine and theme director of genetic research at the Murdoch Children’s Research Institute in Melbourne, explains that every cell in the body needs a constant supply of energy to function normally.

“If there is a disruption, it will affect the function of cells, tissues and organs,” he says.

Christodoulou says that the symptoms of mitochondrial disorders can appear at any age. They can affect any organ and often “many organs at once.”

They can be caused by errors in the genes on our chromosomes (nuclear genes) or genes in our mitochondria (mitochondrial genes). When the error is in a nuclear gene, existing prenatal tests or IVF testing procedures can inform parents about the possibility of the fetus or embryo developing mitochondria, but cannot treat it. However, in most cases involving mitochondrial genes, these tests are not reliable.

There is no effective treatment, but doctors have developed a technique to stop the disorder before birth.

“Replace the mitochondrial genome,” says Christodoulou, through mitochondrial donation.

Law reform

Mitochondrial donation is an IVF-based procedure for carriers of mitochondria, which involves an egg donor.

The United Kingdom legalized the procedure in 2015, and in March Federal Health Minister Greg Hunt, introduced similar legislation to the Australian Parliament.

The bill, named after five-year-old Maeve Hood, who has mitochondrial disease, would allow prospective parents to take the father’s sperm and the mother’s egg with a mutation in their mitochondrial DNA (mtDNA). The nucleus, which has a combination of DNA from the mother and father, is then transferred to a healthy donor egg from which the nucleus has been removed.

The procedure would prevent future mothers from passing on the mutation in their mtDNA by replacing it with healthy mtDNA from the donor egg. Men can carry the mutation but cannot pass it on to their children, except in extremely rare circumstances when the mother also has the same genetic mutation.

Christodoulou says that, with support between partiesThere is hope among the medical community that the legislation will be passed before the end of the year. If it does, the federal government will commit $ 10.3 million to implement it.

The procedure uses the mother’s and father’s nuclear DNA to encode all the individual characteristics of the baby. The role of the donor egg nucleus, says Christodoulou, is to provide “a source of healthy mitochondria.”

The value of mitochondrial donation arises when you understand how deeply the myth “impacts generations of families,” says Sean Murray, one of the founding directors of the Australian Myth Foundation.

“My grandmother is a carrier. Also my mother, my brother and I ”, he says.

For many in the myth community, the myth donation offers the opportunity to avoid the “genetic lottery” involved in reproduction.

Murray says the disease weakens many children.

“Some children may never develop properly. Their muscular systems or brain development may be affected. They will not be able to walk or communicate. And their hearing, visual and learning abilities can be affected. “

Seven year old Alana Catton
“There was nothing that could be done for her from a medical point of view”: Alana Catton, 7. Photography: Catton Family

Like my brother Michael, Toni Catton’s daughter Alana was born very small and struggled to grow, gain weight, or build muscle.

“There was nothing that could be done for her from a medical point of view,” says Toni.

Alana took at least 10 medications a day and was fed through a tube into her stomach. She was never able to walk. He lived in a wheelchair and underwent hours of therapy a week.

“But none of those supportive interventions could stop the progression of the disease. It was quick and brutal, and there was no cure. ”Alana died at the age of seven in September of last year.

‘No designer babies’

Some religious institutions have expressed concern about involving a third person in the reproductive process through the donation of mitochondria.

In presentations made during the public consultation on the proposed law earlier this year, churches raised “ethical issues.”

The Australian Conference of Catholic Bishops said the donation would cause problems by “creating children with three parents,” “genetic bafflement” and “destroying human embryos.” They said the procedure “was not a necessary technology to save lives.”

The Mito Foundation rejects such rhetoric.

“It’s not about editing the DNA within the nucleus, which is what gives us eye color or hair color. It’s not about gene editing, human cloning or designer babies, ”says Murray.

“It’s about taking that very separated and genetically damaged mitochondrial DNA and swapping it out for healthy mitochondrial DNA.”

Beth Hodge, who grew up with a sister whose daily life is affected by a form of myth that she has epilepsy, says that “people may consider donation of myth to be unethical, but they have no idea what myth is like.” .

For the past 27 years, he has seen his sister’s struggle firsthand.

“He cannot cut food, drink water, write.

“If they haven’t seen it firsthand, people don’t understand it,” he says. “It breaks your heart.”

All members of Beth’s family are carriers of the disease. Although Beth is not symptomatic, there is a chance that any child she has will be.

“I would never forgive myself if I had a baby naturally and they were burdened by this condition like my sister is,” he says.

Beth and her partner have been in contact with an IVF clinic since January 2020.

“It has taken them so far to say that our only option, other than using a donor egg without any of my DNA, is to wait for mitochondrial donation to be legal.”

A spokesperson for Hunt said that donating mitochondria had “the potential to change lives and reduce the burden and devastating effects of mitochondrial disease for future generations.”

“When I see that bill, all I see is hope for you and your sister,” says my mother.

“It will give you the opportunity to get tested with the confidence that if you are a carrier of the gene, you will not feel helpless and without options.

“And it will give you the opportunity to have healthy children and a normal life. And, essentially, breaking the genetic chain. “


www.theguardian.com

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