Asking the right questions about genome editing

Laura Blackburn

5 July 2017

The debate surrounding genome editing continues. As you might expect, the Nuffield Council on Bioethics (NCOB) has taken a close interest and is following up its earlier consultation on genome editing technologies with two additional calls for evidence.

In our response to that first consultation, we focused on applications to human health and how debate on medical applications of genome editing, for example in immunotherapies to treat cancers, should not be overwhelmed by the debate on editing of the germline. NCOB highlighted two areas for further review – genome editing in human reproduction and use of editing in agriculture (crop plants and livestock). The first of their additional calls for evidence has been on genome editing in reproduction, released in conjunction with a public survey.

Keeping an eye on the bigger picture

In our response, we outline that while we still think it is important to discuss the ethics of germline editing, we should not neglect the debate on uses of other forms of editing that are closest to application, specifically, those for use in novel therapies and in agriculture.

The potential to edit the genome of eggs, sperm or embryos to stop devastating genetic diseases being passed on to the next generation is a divisive topic that has generated many column inches in the past couple of years. However taking ethical, legal and social issues aside, given the risks and uncertainties associated with editing, we return again to arguments we have touched on previously: why bother to use the technology in this context at all? Nearly all of the same outcomes potentially possible using germline editing can be reached using other reproductive technologies, which do not have the risks and uncertainties associated with germline editing. These include gamete donation and pre-implantation diagnosis, both currently available in the UK and regulated by the Human Fertilisation and Embryology Authority (HFEA).

How far are we prepared to go?

Isn’t it time for an honest discussion around the rights of people to have biologically related children and how far we are prepared to advance technology in order to enable this to happen.

A precedent for altering genetic material that is passed on to the next generation already exists with the approval of mitochondrial replacement. In addition to the main 20,000-gene genome which is found in the nucleus, the organelles that generate energy for the cell, the mitochondria, also have a small 37-gene genome. Mitochondrial replacement is a technique to treat diseases that are caused by mutations in mitochondrial DNA, which are always passed on from mother to offspring. Embryos are created using eggs from a donor with healthy mitochondria – the nucleus from the donor's egg is removed and replaced with that of the patient. Before the approval of this technique, available options included pre-implantation genetic diagnosis which is not a reliable method of detecting some mitochondrial diseases, or estimating their severity. Mitochondrial donation therefore enables women to have children they are genetically related to.

If we are prepared to offer mitochondrial replacement, which alters around 0.2% of the genetic material that is passed on from mother to baby, are we also prepared to consider editing the nuclear genome, to help people avoid passing on devastating genetic diseases to their children? Until relatively recently, editing the nuclear genome was a red line that no-one was prepared to cross. However, opinions are softening – as highlighted by the US National Academies of Science report, released in January 2017, which said that germline editing could be possible in very specific circumstances to prevent the most serious genetic diseases being passed on to future generations.

Equality and robust regulation

In the UK we have robust and clear regulation of reproductive technologies via the HFEA and have measures in place to ensure equity of access to technological advances, as and when they arise, within the health system. Reaching international consensus on the use of gene editing will be more of a challenge due to different cultural, ethical, moral and religious viewpoints. These technologies might be implemented in countries that have more relaxed or no regulatory oversight, potentially putting patients at risk and introducing inequalities through health tourism – those who can afford to travel and pay for access to these technologies will do so. An additional concern might be that individuals conceived as a result of germline interventions are arguably deprived of autonomy, having been exposed to these technologies without their wishes being taken into consideration. Moreover, extensive use in agriculture limits the choice of existing individuals to avoid these technologies should they want to.

Are we asking the right questions?

While human germline editing in humans is the most ethically challenging application of this technology, worthy of all the debate and discussion that has happened so far, it is still a long way off. There must be an urgent shift in the conversation to include applications that are much closer to being realised: in innovative therapies, and for use in agricultural plants and animals. For the latter, it is difficult to forget the handling of the public debate surrounding GM crops in the 1990s and early 2000s and the subsequent public backlash. There is an opportunity to start a nuanced public debate on these issues and to avoid repeating the mistakes of the past. Capabilities in this area are racing ahead and genome editing technologies will be part of our future. We cannot afford to focus the debate on some areas at the expense of others at this crucial junction.

Our updated response is available here