Eight healthy babies were recently conceived via in vitro fertilisation (IVF) in the UK using DNA from three people to avoid inheriting serious genetic mutations, but it could be many years before these procedures are permitted under law in Ireland.
The remarkable scientific development was years in the making.
The procedure is carried out in cases where the mother is known to have a genetic mutation in her mitochondrial DNA – the power house of the cell that makes up human tissue. The mother’s egg is artificially fertilised by the father’s sperm, and the genetic material from this embryo is extracted and transferred to a donor’s egg, one which doesn’t have mitochondrial mutation.
The vast majority of the DNA is that of the mother and father, with the donor only providing less than a tenth of a per cent to the embryo’s genetic code. It nonetheless has the potential to provide hope for families around the world.
Dr Jane Farrar, from Trinity College’s genetics department, explains that mutations in the mitochondria are rare, yet manifest themselves in serious health issues from birth. Babies born with these mutations often suffer brain, heart and muscle failure from a young age as well as developmental delays. Dr Farrar says there is a range of mitochondrial disease with a spectrum of symptoms, all of which are severe.
Leber Hereditary Optic Neuropathy (LHON) can lead to quite sudden, sometimes total loss of vision in both eyes. Dr Farrar says this is an onset disease and often takes place in young adulthood. On the other hand, Leigh Syndrome is a disorder characterised by progressive and gradual loss of muscle use and brain function. This is evident from infancy and early childhood, she says.
The eight healthy babies in the UK were born after about 20 years of genetic and medical research, and in 2015 a change in law allowed for this procedure to be carried out. In spite of the Church of England and other religious leaders questioning its ethics, the UK parliament passed it by a two-thirds majority.
IVF clinics in Ireland are not permitted under law to carry out this procedure. The Department of Health calls it “a relatively new and highly complex form of assisted human reproduction technology”. A department spokesperson said the Health (Assisted Human Reproduction) Act 2024 “establishes a regulatory framework for fertility clinics and assisted human reproduction (AHR) treatments, aiming to ensure consistency, oversight and ethical standards in practice and research”.
The National Infertility Support and Information Group (NISIG) said “while work is under way to establish a regulatory authority for Assisted Human Reproduction (AHR) treatment in Ireland as part of this legislation, research like this in the UK highlights just how far behind Ireland still is in comparison to other countries”.
They said it is imperative the government’s regulatory framework includes an authority that “enables the use of pre-implantation genetic testing (PGT) of embryos; posthumous assisted human reproduction; and embryo and stem cell research”.
Dr John Waterstone, a graduate of Trinity College’s genetics department as well as its medical school, is the founder and director of Waterstone Clinic, one of Ireland’s largest IVF providers. While he acknowledges the “very experimental” nature of the procedure, he says “it is pretty remarkable that they’ve managed to do it. It’s an incredible achievement for them”.
He says that for some “it’s ethically questionable” to facilitate genetic modification of embryos but adds that this is for “couples who have found themselves in tragic situations. Really traumatic, horrendous experiences of parents’ children dying in infancy after being born with rare genetic mutations”.
Waterstone Clinic does provide pre-implantation genetic testing on embryos to discover if parents are unknowingly passing down genetic mutations that could cause serious health conditions in their children. However, Dr Waterstone says that the kind of procedure that took place in the UK is unlikely to come to Ireland anytime soon.
“I don’t really think in the foreseeable future that anyone in Ireland who’s diagnosed with mitochondrial disease will receive that treatment here. It’s more viable to go to the UK,” he says. Given the rarity of these mutations, “one in 5,000 individuals might have mitochondrial diseases”, he says and the necessity for this treatment is not widespread.
