“Maeve’s Law” would allow IVF parents access to technology to prevent mitochondrial disease. This is what the Senate is debating

The Senate is debating this week ‘Maeve’s Law’ – a proposal to legalize access to new assisted reproductive technologies that will reduce the risk of parents passing mitochondrial disease to their children.

Maeve with her mother Sarah Hood.
Photo courtesy of the Hood family, Author provided

The legislation, officially called the Mitochondrial Donation Law (Maeve’s Law) Reform Bill 2021, is named after Maeve Hood, a six-year-old Victorian girl who lives with Leigh syndrome – a disorder in which the cells of the body do not produce enough energy. Tragically, Maeve is unlikely to survive beyond childhood.

The vote expected this week will be the first conscience vote in the Senate since historic reforms to allow marriage equality in 2017, and is already the subject of heated debate.

But the issues raised are probably not new. These reforms have already been the subject of extensive community consultation and have been approved by the House of Representatives.

What is mitochondria donation?

Mitochondria are energy-producing structures inside cells, which have their own DNA and are separate from the cell nucleus containing most of the cell’s DNA (called “nuclear DNA”). Mitochondrial DNA is entirely inherited from the mother’s egg, so if a mother has mutations in her mitochondrial DNA, she risks passing life-threatening conditions to her baby.

Conceiving a baby through mitochondrial donation involves implanting the mother’s nuclear DNA into a healthy egg from which the nuclear genes have been removed, and using that egg for in vitro fertilization (IVF) with a sperm. Alternatively, a procedure called pronuclear transfer can be used early in the fertilization process a few hours after the sperm has entered the egg, but before the parental genomes come together and the fertilized egg officially becomes an embryo.

Block diagram of mitochondria donation

Mito Foundation

A child born by mitochondrial donation would inherit a mixture of nuclear DNA from his mother and father, as usually happens, as well as healthy mitochondrial DNA from the egg donor.

As a result, the donation of mitochondria has sometimes been described as creating “three parent babies”. But “2,002 baby parents” would probably be more accurate, given that there are only 37 mitochondrial genes, compared to at least 20,000 in our nuclear DNA.

Read more: 3-parent IVF could prevent disease in many children (but it’s really more like 2,002-parent IVF)

Australian law currently prohibits the creation of a human embryo that involves the genetic material of more than two people. The ban was introduced nearly 20 years ago amid fears that IVF and embryo research could lead to ‘designer babies’ and cloning. Maeve’s Law would change this specifically to allow the donation of mitochondria to prevent mitochondrial disease.

The debate around the issue has centered on a series of questions, such as: is there a risk that the child could still end up with mutant mitochondrial DNA? Are there ethical issues centering on the unborn baby’s inability to give consent? What are the rights of the egg donor? Does the procedure carry any other health or genetic risks?

The expert eye

In the UK, where mitochondria donation research was first, four scientific reviews by the Human Fertilization and Embryology Authority and a survey by the Nuffield Council on Bioethics were carried out between 2011 and 2016. These reviews resulted in the general conclusion that the advantages outweigh the disadvantages. if regulated appropriately, and Britain legalized mitochondria donation in 2015.

In Australia, mitochondria donation has been the subject of a series of investigations, including a Senate inquiry in 2018 and a review by the National Health and Medical Research Council (NHMRC), which looked into these issues. with a fresh look.

In response, the government drafted Maeve’s Law, which went through a series of reviews and public consultations, and won the support of 60 leading Australian experts.

Does the public support it?

A challenge in gauging public support is to gauge genuine community sentiment, rather than inviting submissions that simply serve as a forum for people with strong opinions for or against mitochondria donation.

To address this challenge, researchers convened a citizens’ jury in 2017, and the NHMRC held a citizens’ panel in 2019 to assess attitudes toward mitochondria donation. Both offered skilled support to enable the technology.

What topics are likely to be contentious in the Senate debate?

The Senate will likely reconsider the amendments that were defeated in the House of Representatives in December. These include a proposal to only allow the technique in which the mother’s DNA is implanted into the donor egg before fertilization with the father’s sperm.

This suggestion is a response to fears that pronuclear transfer may lead to increased embryo destruction rates.

But these early fertilized eggs — also called zygotes — don’t meet the legal or biological definition of an embryo, and most embryologists don’t consider the technique to cause more embryo loss than other assisted reproductive technologies. Furthermore, banning this approach could seriously jeopardize the development of mitochondria donation in Australia.

Zygote undergoing pronuclear transfer
A zygote about to have its nuclear DNA removed and transferred to a donor egg, about 20 hours before division to form a two-cell embryo. The arrows show the DNA of the mother and the father, called “pronuclei”. These remain separate until later in the process, hence why the zygote is not considered an embryo.
Courtesy of Louise Hyslop and Mary Herbert, Univ. Newcastle-upon-Tyne

Maeve’s Law will still require researchers to report to NHMRC on the eggs and embryos used in their research, to seek ways to minimize the numbers used, and to report to Parliament on an annual basis.

Read more: Disputes over early life may block advanced reproductive technologies such as mitochondria replacement therapies

If not now when?

While we must respect the differing attitudes towards IVF and embryo research, we believe that most experts and members of the public recognize the importance of giving couples at risk for mitochondrial disease the best chances of having a healthy child.

Maeve’s Law has been carefully drafted to ensure careful introduction and evaluation of mitochondria donation technology. The technology will be in a clinical trial setting for at least ten years, during which time the health of babies born using these techniques will be carefully monitored.

Science backs it up. The community supports him. People affected by mitochondrial disease have long supported it. We ask senators to support it.

About Norman Griggs

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