The UK government has decided to consult publicly on the introduction of regulations to allow mitochondrial donation.
I suspect that at the majority of people in the UK have no idea what mitochondrial donation is, what the risks and technical issues are, or what the ethical considerations might be. I wasn’t until very recently!
This short note attempts to give a very brief introduction to the concept and raise some considerations that might inform the discussion. It is not an expert paper – I am not an expert, but it is an overview to prompt further thought and discussion by the majority of UK citizens, who are also not experts. A source of information on the topic is “Novel techniques for the prevention of mitochondrial DNA disorders: an ethical review”.
What is Mitochondrial donation?
The majority of human DNA is contained in the cell nucleus, however some is contained in the mothers mitochondria – so called Mitochondrial DNA. Mutations or abnormalities in mitochondrial DNA (as in all DNA) can lead to disorders in the developing offspring. Since these disorders are due to the DNA, they are not curable.
“They are progressive, can be very seriously debilitating and disabling. They may also cause miscarriage and stillbirth, death in babies, children and young people, or severe symptoms which onset in adulthood. The symptoms and the age and severity at which they are experienced vary widely between patients, which can make diagnosis difficult. Mitochondrial disorders may affect one organ at a time – for example resulting in blindness or heart failure – or may affect several areas of the body at the same time. Mothers can pass on mitochondrial disorders without having experienced symptoms themselves, which in some cases may mean that they are not aware that they carry mutated mitochondrial DNA that can cause disorders in their children.”[i]
Mitochondria are separate ‘bags’ within a cell, and so can be separated and removed from a cell. They can be transferred from cell to cell, and so in theory the mitochondria from a parent whose DNA is abnormal can be removed and then replaced with mitochondria from another person who has normal DNA. The new cell then contains DNA from the female nucleus donor and the father, and a small proportion of DNA from the mitochondria donor.
As with all new technology, implementation is far more difficult than the theory. However, experimenters believe they are making progress. Around 30 children worldwide have been born using a technique whereby mitochondria from a donor are injected into the mother cell, providing an excess of mitochondria, in effect trying to dilute the faulty mitochondria. These trials have indicated a higher than normal incidence of Turners Syndrome (which resulted in miscarriage and a termination), a lack of ovarian development at puberty and short stature. It may be associated with problems with major organs and mild learning difficulties.
What are some of the risks?
What loving person cannot want to improve the life of another in the best way they can? If I were a scientist researching mitochondrial diseases I would use all of my expertise to try to find solutions. In my own job as a design engineer I am continually striving to improve our product, and I sometimes get immensely frustrated by the procedures and processes that are put in place to make sure that new developments are as risk free as possible. New concepts that I think are very likely to work are often years in development and testing before being introduced into a machine. But I accept the situation because of the consequences of something going wrong. A similar situation must apply with Mitochondrial donation.
The amount of testing and refinement that is needed with a new technology depends on the impact if it goes wrong. Let’s consider some of the impacts if mitochondrial donation were to go wrong.
- Being genetic, the outcome of the genetic manipulation will be permanently in the gene pool of the descendants. Our knowledge of how DNA works is still very limited. Only a few years ago scientists labelled most of the human DNA as ‘junk’, but now controversial recent research is showing that what was previously written off as junk may be important in helping each cell become the type of cell that it needs to be.[ii] There must be a risk that future generations will suffer unknown and unpredictable consequences of ‘unnatural’ DNA mixing.
- We really don’t understand how DNA forms our developing body. We know that a single DNA change can make the difference between a fruit fly having two or four wings, but we don’t know how that happens. Humans comprise 50 trillion cells, yet our DNA string only contains 3 billion base pairs. That’s more than 10,000 cells per base pair. We don’t know exactly how so few DNA base pairs can manufacture such a complex entity as a human, although applying engineering principles we can infer that the cell itself must be an intelligent component.[iii] How will that cell respond to the modified mitochondrial DNA from a donor? Would it be like running Microsoft software on an Apple computer?
- The body has evolved to reject unviable embryos. The trials mentioned above showed that this happens. Might mitochondrial donation lead to an increase in miscarriages and terminations? Would the stress and damage to the mother and couple exceed the risk of mitochondrial disease?
- If mitochondrial donation techniques were to become widespread, but only effective for a proportion cases, what would be the consequence on those parents who still have ‘disabled’ children? Would the emotional strain be even greater than today? Would society shun or blame them for having disabled children?
- We learnt above that often a mother will not know that she has a disorder. For such parents mitochondrial donation will not be an option, unless there is a universal screening program. What would be the social and emotional impacts of such a program?
Questioning our assumptions
These are of course only a few of the questions that need to be considered. However, perhaps it is also important to consider the cultural assumptions that we might be unknowingly making when considering the issues.
A parent will always want the best for their children. If one were to ask any couple, “would you like a healthy or unhealthy child” then I cannot imagine any couple opting for the latter. However, if you were to ask the parent of a disabled child, “would you rather have Julie or not have Julie” the responses would not be so clear-cut. If you were to ask “would you rather have Julie but that Julie was not disabled” then the responses would probably lean towards the not disabled Julie.
Anyone who loves others would love to see them fully healthy, intelligent, happy, hard-working, fulfilled, loving and loved, friendly, etc. etc. Whilst the attributes and character traits of an individual are interlinked, they are not directly and positively correlated. Health doesn’t lead to happiness. Intelligence doesn’t lead to being loving or loved. So we must be wary of concluding that it would have been better if Julie had been born healthy. She may be more loved, more fulfilled and happier being disabled than she would have been if she had been healthy. Would Stephen Hawking have become the great physicist that he is if he had not been disabled?
We assume that a long life is better than a short life. Is this correct? How do older people think about this? Are the years in our life more important than the life in our years?
Are we convinced that the end of this life is the end of everything? If not, then why do we want to keep people from dying? Is it for their sake or ours?
What aspects of life are important, what we produce or the relationships we forge?
Is suffering always a bad thing? What does evidence suggest? Would South Africa have successfully transitioned from apartheid to democracy without Mandela suffering years of imprisonment?
This short post was prompted by the UK government’s intention to introduce regulations to allow mitochondrial donation.
We need to question that intention. This is not an issue to approach lightly and quickly. Consideration goes beyond the term of a single parliament, and beyond single countries. I do not feel comfortable that our government, elected by only a small proportion of the population, seems to be intent on adopting a technology which could have severe consequences.
What do you think?