Mitochondrial Disease

Mary Glindon Excerpts

Tuesday 25th June 2013 Westminster Hall

[Chi Onwurah (Newcastle upon Tyne Central) (Lab)]

It is a great pleasure to serve under your chairmanship, Mr Davies. I am pleased to be able to lead a debate on this most important subject. I shall speak about mitochondrial disease, the devastation it causes and the new techniques developed by Newcastle university to prevent it. I declare an interest in that my father studied medicine at Newcastle, so I am a natural champion of that great university’s medical research and innovation. I am here primarily to champion not Newcastle university however, but the interests of my constituents struck down by mitochondrial disease, and indeed all those who suffer from it.

The subject is technical and I will attempt to be as clear as possible in setting out the arguments. Mitochondria are found in every cell in the human body, except red blood cells. They are the batteries generating energy for the cell. Mitochondria convert the energy of food molecules into the energy that powers the cell’s functions. About 200 children are born every year with a mitochondrial disease. Such diseases are passed from mothers to their children and are caused by faulty mitochondria. Like all DNA, the DNA in mitochondria can mutate and mothers can pass those mutations on to their children. Faulty mitochondria mean that the cells are unable to function normally and the diseases caused by them can have a devastating effect on families. The diseases tend to affect parts of the body that use a lot of energy, such as the brain, muscles, nerves, liver, kidney and heart, and vary widely in severity, from life-threatening to having few or no obvious symptoms. Symptoms vary, but can include poor growth, muscle weakness, tiredness, poor co-ordination, and sensory, respiratory or cognitive problems.

There are no effective treatments available for serious mitochondrial disease. When the cells go wrong, it can result in serious conditions, including blindness, fatal heart failure, liver failure, learning disabilities and diabetes, and can lead to death in early infancy. Prevention is the only realistic option. In 2010, Newcastle university scientists, with funding from the Wellcome Trust, pioneered research into variations of in vitro fertilisation procedures that could prevent the transmission of the genetic mutations that cause these devastating disorders. The techniques use part of an egg donated by a healthy individual, to replace the faulty mitochondria of the affected mother. The intention is to give affected families a chance to have healthy children that are genetically related to them, but born free of mitochondrial disorders. Such techniques are not currently permitted in the UK, but legislation allows the Government to introduce secondary legislation that would allow the treatments to be used.

Mitochondrial disease can blight families for generations, because, as I said, it is passed from the mother to child during pregnancy. The techniques could put a stop to it, by preventing the faulty mitochondria from being passed to the embryo. Mitochondrial disease affects about 6,000 adults in the UK. In my constituency, four families—Bumstead, Cass, Bland and Mahmood—suffer from mitochondrial disease. Although every effort is being made to help them, there is no cure. For example, Lily Cass, who is in her 70s now, has five brothers and three sisters, and one brother who died at 56. They are all affected in different ways by mitochondrial diseases, and some more severely than others. Some days, Lily can hardly move due to lack of energy caused by her faulty mitochondria, which takes all her strength away. She has four children, including a daughter, who is likely to pass the disease on to her children. She worries about that all the time.

For those women and their families, the most important help we can offer is potential treatments, to prevent the next generation of patients from being affected. The opportunity to have their own children free of disease is something that the patients understandably want.

As with all such advances, it is right that the ethics are properly considered before techniques are adopted, and the Minister will be aware that concerns have been raised. There are those who argue that the techniques create children with three parents, but the embryo would carry only a small number of genes from the donor—just 13 out of 23,000, or 0.056% of the genetic material. How much of a parent is that? The function of the 13 genes is restricted to powering the mitochondria; they do not affect personal characteristics such as eye or hair colour, or behaviour.

Last June, the Nuffield Council on Bioethics produced a report that found that the technique would be an ethical treatment option for affected families, as long as research showed that treatment was likely to be safe and effective, and families were offered full information and support. The council’s report found that no strong cultural or social emphasis is generally placed on mitochondrial inheritance as a specific element of personal identity. Many of the social and biological aspects that typically imply a “parent”, and may be relevant in egg donation for reproduction, do not apply to mitochondrial donation. The council therefore suggested that if the treatments were made available, mitochondrial donors should not have the same status in regulation as reproductive egg donors.

[Mrs Mary Glindon (North Tyneside) (Lab)]

My hon. Friend makes a good case about the serious effects that the diseases resulting from the condition have on families. If we think forward to any children who are fortunate enough to be born without disease because of the treatment, would there be any possibility that they might consider themselves to have three parents, whether or not they had any traits from the third one? Has thought been given to how that would be considered if it should happen?

[Chi Onwurah]

My hon. Friend is right. There has been some debate about the status not only of the donors but, most importantly, of the children. The Nuffield Council on Bioethics says that families must be offered full information and support, and that must also apply to the children, so that they understand the scientific nature of the very limited gene inheritance from the donation.

If mitochondrial donors were not given the same status as reproductive egg donors, it would be not legally required for them to be identifiable to people born from their donations. The council concluded that the proposed treatments would be a form of gene therapy that would permanently cure the disease in future generations. Changes resulting from the replacement of mitochondrial DNA would be passed on not only to the resulting children, but to the descendants of any girls born from the techniques, via their eggs.

Dr Geoff Watts, who chaired the inquiry, said:

“We understand that some people concerned about the idea of germline therapies may fear that if such treatments for mitochondrial gene disorders were approved, a ‘slippery slope’ would be created towards comparable alterations to the nuclear genome.”

That is an understandable fear, but he went on to make a very important point:

“However, we are only talking about the use of these techniques in the clearly-defined situation of otherwise incurable mitochondrial disorders, under strict regulation.”

In 2012, the Human Fertilisation and Embryology Authority—HFEA—launched a public consultation on mitochondria replacement. It interviewed almost 1,000 people, and a further 1,800 completed questionnaires. It also organised public workshops around the UK and spoke to individuals affected by the diseases, to gauge their views. It published the results in March of this year, and found broad public support for the use of the technique.

The HFEA asked four main questions about attitudes to the gene treatment of mitochondrial diseases. When asked about attitudes to the selection of embryos based on testing, 65% of those questioned were positive or very positive, with only 8% negative. When asked about altering the genetic make-up of an egg or an embryo, 56% were positive or very positive and only 10% were negative. Attitudes to the use of genetic material from a third person showed that 44% were positive or very positive, with only 15% negative. The HFEA therefore advised the Government that there was broad support for mitochondrial replacement being made available to families at risk of passing on a serious mitochondrial disease. It also advised that if treatment were to be authorised by Parliament, it should be under certain conditions, such as its being available only in licensed clinics.

The HFEA recommendations have been widely welcomed by campaigners. For example, Dr Marita Pohlschmidt, director of research at the Muscular Dystrophy Campaign, said:

“We welcome this outcome. There is currently no effective treatment available for mitochondrial diseases, and at this time, prevention remains our strongest option. By taking forward research into pro nuclear IVF, we move towards giving women living with these devastating and unpredictable conditions the choice to bear their own unaffected children. This technique does involve a step into new scientific territory. But it is a calculated, specific step with the sole aim of preventing a potential fatal condition from being passed down to the next generation, where possible.”

We are now waiting for a decision from the Government about whether secondary legislation that will allow the techniques to be licensed for use in patients will be introduced in this parliamentary Session. It has taken years to get to this stage, and it is important that progress does not stall because families are waiting for this. Introducing regulations now will ensure there is no avoidable delay in the treatments reaching affected families once research is completed and the HFEA considers there to be sufficient evidence that the techniques are safe and effective.

I called this debate to hear an update from the Minister on the progress that she has made, and to ask when we can expect a decision, and when we can expect to see legislation.