Scientists announced this week that they had mastered a technique for editing the genes of a human embryo in order to prevent inherited diseases from passing down the generations.
The breakthrough has the potential for ridding the world of many conditions that are otherwise incurable. But the technique involves making permanent changes to a human being’s DNA and that of all its offspring. Should we welcome this development or resist it?
Scientists at the Oregon Health and Science University and Salk Institute in the United States, working with colleagues in both South Korea and China, have successfully used a technique that edits the gene of a human embryo to repair a DNA mutation that causes a heart condition called hypertrophic cardiomyopathy. This inherited condition affects one in five hundred people and is the commonest cause of sudden death in otherwise healthy young athletes.
The researchers created an embryo by injecting the eggs of IVF donors with the sperm of men who carried the gene that caused the condition along with an enzyme that serves to repair the gene so that the condition cannot be passed on. Previous attempts to master the technique had failed, partly because they had succeeded in affecting only some but not all of the cells in the embryo. The latest work, however, showed the gene-editing affecting all cells, allowing the genes of the embryo then to develop normally. Some scientists had feared this technique would cause ‘off-target’ genetic damage as a side effect, but in the latest work there was no sign of this.
Shoukhrat Mitalipov, the director of the Centre for Embryonic Cell and Gene Therapy at Oregon Health and Science University, said of the implications of this development: ‘Every [future] generation would carry this repair because we’ve removed the disease-causing gene variant from that family’s lineage. By using this technique it’s possible to reduce the burden of this heritable disease on the family and eventually the human population’.
Although this particular case specifically involved eliminating hypertrophic cardiomyopathy, the technique is in principle applicable to very many more inheritable diseases including Huntington’s disease, sickle-cell anaemia and cystic fibrosis.
The work in Oregon was done on early-stage human embryos that were never intended for implanting in a womb with the aim of creating an actual human being. That would have been unlawful in the United States as it is in Britain where our Human Fertilisation Embryology Act bans the implanting of genetically-edited embryos. Such genetic editing can be done only for research purposes. But if research continues to make progress such as the Oregon doctors were able to announce this week then the question of whether we should allow gene-editing in IVF treatment is bound to become pressing.
This may be some way off. There is still plenty of work to be done for us to be sure that there are no unintended, damaging consequences in the process.
But given the enormous implications of allowing human beings to be born from gene-edited embryos, the debate cannot start early enough.
The advantages of changing the law to allow for the implanting of a gene-edited embryo in a womb are obvious enough. Not only would it relieve parents of the burden of passing on genes they know might well cause disease in their children and all subsequent generations, but it also has the potential for ridding the world of such inherited diseases once the technique of gene-editing becomes widespread. This would be a major contribution to relieving human suffering as well as providing economic benefits to humanity.
But the potential disadvantages may be no less real. The most obvious is that gene-editing is for good: that, indeed, is how it works. In other words, once a gene is modified it is modified forever and if damaging side effects are discovered way down the line, notwithstanding efforts made now to see whether they exist or not, we could find ourselves saddled with harmful effects we have either to put up with or to try to eliminate with yet further gene-editing, creating yet further sources of uncertainty. Put simply, if we can never be sure of the effects of our actions, we should act with intense caution especially when those effects are permanent.
A quite separate concern is that the technique of gene editing potentially provides the rich with a means permanently to entrench their advantage. This is the spectre of the so-called ‘designer baby’, the child specifically tailored both to exclude all deficiencies and to enhance all advantages. Such babies, it’s argued, would then themselves produce dynasties of the advantaged.
Faced with these drawbacks, some sceptics of gene-editing argue that it is in any case unnecessary. They point out that it is already legal for people using IVF to choose, before implantation in the womb, between different embryos so as to minimise the risk of inherited diseases being passed on. Their opponents, however, argue that such choice does not deal with all cases of inherited disease and that the risk of some inherited diseases being passed on can be eliminated only by gene-editing techniques that actually get rid of the disease-passing gene for all time.
This debate is bound to be slow-moving. Ethical discussion about whether ‘three-parent babies’ (in which a mother’s faulty mitochondria can be replaced in a pre-implantation embryo by those of another woman) was conducted for ten years before Britain’s Human Fertilisation and Embryology Authority gave the go-ahead. On gene-editing, the question is whether the science will move faster than the debate.
What’s your view? Does this week’s announcement of scientists’ latest advance in gene-editing fill you more with hope or alarm? How worried (or not) are you about the possible unintended consequences of gene-editing? Do you think further research can be sufficiently thorough to allay any fears we all may have about as-yet unknown side effects? And do you think the potential advantages of gene-editing are sufficiently great for us to be ready to take risks?