Dave Sharma (Wentworth, Liberal Party) Share this | Hansard source

I rise to speak on the Mitochondrial Donation Law Reform (Maeve's Law) Bill 2021. We've received a good lesson in some of the medicine, science and ethics from the two previous speakers on the other side, and I commend their remarks. This is obviously a deeply personal issue for many people, and I respect that people will have differing views on this. From my own perspective, I look at this as someone who very much believes in the power of science to improve human lives. Our success as a species has relied upon harnessing science and knowledge, and all the traditions that come with them, to make our lives a little less nasty, a little less brutish and a little less short.

The subject we're discussing today, mitochondrial donation law reform, relates to mitochondria, the very small structures in our cells which generate the energy that powers every part of our body. They provide us with the energy our body needs to walk, to talk, to laugh, to hear, to digest food, to function and to breathe. They do this by generating adenosine triphosphate, which is used by the cells in which they sit as a source of chemical energy, and they generate this from glucose and oxygen.

All cells in the human body other than red blood cells have mitochondria, but what makes mitochondria somewhat unusual is that they have their own DNA, or deoxyribonucleic acid, which controls their function and, critically, also controls their energy production. Mitochondria, as previous speakers have said, are inherited exclusively from the mother, which means that mitochondrial DNA is passed on from the mother only. It's important to understand that this is quite separate from our nuclear DNA, which sits at the centre of us. Nuclear DNA comes from both our parents and informs who we are, our appearance, our personality and various other attributes.

Mitochondrial disease is a defect in these energy-generating structures within our cells. It's a debilitating disorder that robs the body's cells of energy, which usually causes multiple organ dysfunction failure and frequently death, because when mitochondria are faulty the body does not get the correct level of energy it needs to function. Depending on the person and the form of mitochondrial disease they have, they may suffer symptoms ranging from loss of motor control, strokes, seizures, visual or hearing problems, cardiac or liver disease, developmental delay or intellectual disability. The impact of such diseases, as you can imagine, can be devastating, and virtually all forms of mitochondrial disease have a significant impact on patients and those who care for them, including their parents. Babies and young children frequently die of Leigh disease, a form of mitochondrial disease.

Mitochondrial diseases can impact on sufferers in different ways. Many people with mitochondrial disease end up having repeated and prolonged visits to hospitals for treatment, which is invariably inadequate because it's not a disease that can be treated. They can present with things like temporary blindness or deafness, strokes, balance difficulties and digestive or eating difficulties, all of which require significant treatment and care. The fact that they will have repeated seizures or loss of motor control means that people of all ages suffering from this disease will usually not be able to work. They will often need full-time care. It will have a pretty broad impact on their family and social circles.

In some cases, mitochondrial disease is caused by genetic mutations in the nuclear DNA that we inherit from both our parents. Mitochondrial disease can also arise as a spontaneous genetic mistake at conception. But, in about half of all known cases, mitochondrial diseases are caused by mutations or defects in the separate mitochondrial DNA that we inherit solely from our mother. Around one in 200 people or around 120,000 Australians carry a mutation in their mitochondrial DNA that could potentially cause the disease. It is likely that defects in the mitochondrial DNA are much more common in the community than previously thought.

Around one in 5,000 Australian babies are born with a severely disabling form of mitochondrial disease that can cause death in infancy, childhood or adulthood, which is more than one every week. In Australia, there are about 56 children born each year with a very severe form of the disease, with the prognosis being that most of these children will die within their first five years.

Like many people here, I expect, I have members of my own electorate who have a story to tell. I had a couple, Vanessa and Tom Fennell, who sadly lost their 11-month-old daughter, Sibella, to mitochondrial disease in 2014. I met with Vanessa in July last year when she shared her tragic personal story and she told me about her view and her belief that legislative changes that would legalise mitochondrial donation would have a positive impact for parents like her.

It is possible to significantly reduce the risk of mitochondrial disease being passed on. That mitochondrial disease which is caused by defects in the nuclear genes can often be prevented through prenatal testing or an IVF based procedure called pre-implantation genetic diagnosis, but these approaches are generally not as reliable when the mutation is in mitochondrial DNA inherited from the mother. In this situation, mitochondrial donation is an alternative approach. Mitochondrial donation, the topic that we were discussing today, is an assisted reproductive technology that, when combined with invitro fertilisation, or IVF, has the potential to allow women whose mitochondria would otherwise predispose their potential children to mitochondrial disease have a biological child who will not inherit that predisposition. It does this by a complex process of creating an embryo which includes nuclear DNA from the two parents and mitochondrial DNA from a third party, a different woman as the mitochondrial donor.

Mitochondrial donation involves removing the nuclear DNA from the patient's egg containing faulty mitochondria and inserting it into a healthy donor egg which has had its nuclear DNA removed. This prevents mitochondrial DNA defects from being inherited by an otherwise genetically related offspring. It breaks the chain of transmission, if you like. So mitochondrial donation can minimise the risk of the transmission of a prospective mother's mitochondria and prevent future generations from inheriting these severe and debilitating diseases.

The purpose of this bill, the Mitochondrial Donation Law Reform (Maeve's Law) Bill 2021, is to amend existing Commonwealth legislation to allow such mitochondrial donation to be introduced into Australia for research and for human reproductive purposes. The key federal laws governing this area are the Prohibition of Human Cloning for Reproduction Act 2002 and the Research Involving Human Embryos Act 2002. These laws currently prohibit the implantation of a human embryo that contains more than two people's genetic material. This is regardless of whether that material is simply transferred, as it is in mitochondrial donation, or where genetic modification is proposed. Changing the law here, which is what this bill proposes to do, is critical to allowing affected individuals the opportunity to have genetically related children without the risk of them inheriting mitochondrial DNA defects which will drastically limit their lives.

In 2018, the Senate Community Affairs References Committee undertook an inquiry into mitochondrial disease and related matters. Reporting in June of that year, they made a series of recommendations, including that public consultation be undertaken about the introduction of mitochondrial donation reforms. Over 2019 and 2020 the NHMRC, the National Health Medical Research Council, undertook a series of consultation activities. These were informed by experience in the United Kingdom, where mitochondrial donation has been lawful since 2015. The outcome of these inquiries and the overseas experience have shaped this bill, which outlines, in my view, a carefully staged pathway towards the legalisation of mitochondrial donation in clinical practice.

A two-stage implementation process is proposed in this bill, with mitochondrial donation initially being legalised for certain research and training purposes and to support selection and licensing of a pilot program to deliver mitochondrial donation to impacted families. Stage 2 would then allow or permit mitochondrial donation in clinical practice more broadly, depending upon the outcomes and an evaluation of the initial pilot program.

Mitochondrial donation cannot be used to cure people with existing mitochondrial disease, nor can it prevent mitochondrial disease caused by changes occurring in an individual's nuclear DNA. Mitochondrial donation can, however, minimise the risk of transmission of the prospective mother's mitochondria and, in doing so, prevent future generations from inheriting these severe and debilitating diseases. What this means in practice is that other children and parents like Sibella and her parents, Vanessa and Tom, will not have to suffer the devastating consequences of mitochondrial disease.

There are some who have ethical concerns with this legislation. We've heard from some tonight already, and I expect we will hear from more. I respect that, but I also believe that all of the advances we have had as a species, as humanity, have relied upon the embrace of science and technology to protect people from disease and to prolong human life. It's the harnessing of science, medicine and modern empiricism that has led to the doubling of our life expectancy in the last 100 years alone. All of us here are beneficiaries of modern medicine and modern science, and I do not believe that we can stand in the way or deny this to others. That's why I support this legislation, and I commend it to the House.

See this speech in context