4 February 2015
A crucial vote in the UK House of Commons has passed in favour of changes to the law that would permit the use of mitochondrial transfer or ‘3-person IVF’.
The controversial term refers to different methods to create healthy genetic children from mothers with diseased mitochondria that would otherwise be passed on to their offspring, resulting in severe mitochondrial disease.
The three people technically involved are the biological father, biological mother and an egg donor; essentially, manipulation before (maternal spindle transfer) or after fertilisation (pronuclear transfer) is used to remove the nuclear genetic material from the donor cell with healthy mitochondria and replace it with that from the mother’s egg cell. Thus, the vast majority of maternal DNA in the subsequent embryo comes from the biological mother; only the small amounts of mitochondrial DNA come from the female donor. However, this mitochondrial DNA would be passed on to subsequent generations, and thus technically constitute a heritable genetic modification, which is why it is not currently legal anywhere in the world.
The final vote was 382 in favour and 128 against implementing modifications to the Human Fertilisation and Embryology Act to permit use of the technique. Importantly, its use would still be subject to regulatory control by the Human Fertilisation and Embryology Authority (HFEA), expected to be on a case-by-case basis.
There is one final milestone before the proposed changes would be enshrined in law, an additional vote in the House of Lords. If passed (the expected outcome), then the law will be changed to specifically exempt the use of mitochondrial transfer from the general prohibition against heritable genetic modification of humans. Some opponents of the change fear that this move will be incompatible with EU law; others have ethical or safety worries, including the US Food and Drug Administration (FDA) who have expressed concern over the potential for harmful epigenetic changes or re-emergent mitochondrial disease in future generations following mitochondrial transfer; according to the Telegraph, Prof Evan Snyder, who chaired the FDA committee on mitochondrial transfer last year has warned the HFEA against letting the technique be used.
However, patients, patient groups and many scientists were jubilant following the yes vote; Dr Jeremy Farrar, Director of the Wellcome Trust, which funds mitochondrial research including transfer techniques, commented:“This is a vote of confidence in the patients, scientists, doctors and ethicists who have worked hard for a decade to explain this complex research to politicians, the public and the media, and in the exemplary process for reviewing scientific, ethical and public opinion led by the Human Fertilisation and Embryology Authority”. For some affected families it may mean the possibility of having further children that are genetically related to both parents but without the serious disease present in their older sibling/s.
Conversely MP Fiona Bruce, opposing the motion in the Commons debate said that: "the implications of this simply cannot be predicted. But one thing is for sure, once this alteration has taken place, as someone has said, once the gene is out of the bottle, once these procedures that we're asked to authorise today go ahead, there will be no going back for society" .
The BBC notes that the first baby produced using the technique could be born as early as 2016, although this may be jumping the gun slightly – the technique will be legal, but only where permitted by the HFEA, who have said they wish to see some additional safety checks performed first. As the technique would only be suitable for a subset of families affected by severe mitochondrial disease, and as yet only two centres in the UK have the required technical expertise, the number of applications to the HFEA each year is expected to be fairly small.
Long-term monitoring of children born following the use of the technique and indeed of their children is desirable, to determine whether any safety issues genuinely do arise, although who would fund such surveillance remains unclear.