The complex genetic procedures approved by the House of Commons on Tuesday were a headline writer’s dream. No need to get “mitochondrial donation” into a single column, when the shock effect of “three-parent” embryo and “designer baby” would fit and helpfully scare readers into reading. As the old newspaper maxim puts it, however, “don’t let the truth get in the way of a good story”.
The controversial gene therapy would no more make a “third parent” out of a woman who contributes a small quantity of her DNA to a couple than a heart transplant would transform a recipient into someone else or invest in the donor some new familial relationship. But the “culture war” that is the abortion/life/IVF debate has opened up a new international front and we can expect the usual hyperbole.
Mitochondria are small “battery packs” inside the body’s cells that convert food into energy for cells to function. They have their own DNA – 0.054 per cent of overall DNA – which only controls mitochondrial function and energy production and remains outside the nucleus of the egg.
Incurable conditions
If faulty, they can cause inherited conditions such as fatal heart problems, liver failure, brain disorders, blindness and muscular dystrophy, incurable conditions passed down the maternal line, which are believed to affect around one in 6,500 children worldwide.
By removing the nucleus of the mother’s fertilised or unfertilised egg, the part containing key genetic instructions that determine our characteristics as individuals such as personality, hair and eye colour, and inserting it into an egg from another woman which has had its nucleus removed but has healthy mitochondria, doctors can implant the renovated egg back in the mother’s uterus to produce a healthy child.
The technique draws on those well-established methods developed in the widespread practice of in vitro fertilisation (IVF) – five million of the world’s babies have now been conceived via IVF.
Studies suggest that 2,500 women in the UK and 12,400 in the US could benefit from the new procedure – 150 and 770 births a year respectively. If the House of Lords backs its licensing, the UK will be the first state in the world to embrace the new technique.
In the US it remains problematic. The National Institute for Health may not fund research that involves discarding surplus donor eggs, while the Food and Drug Administration argues that the “full spectrum of risks . . . has yet to be identified”.
For those opposed to mitochondrial donation there are two other key ethical dilemmas. On the one hand, like its position on IVF, the Catholic Church regards the need to produce and discard surplus, unused donor eggs as akin to the abortion-like destruction of foetuses, of life.
Supporters of IVF and the new technique say it is wrong to regard the egg before implantation in the womb as human life with all its rights and that the production and discarding of eggs is a natural part of the menstrual cycle.
In Ireland, in the absence of any legislative regulation of assisted human fertility , mitochondrial donation would probably fall foul of Irish Medical Council guidelines, although in Roche v Roche the Supreme Court has found that the egg at pre-implantation stage can not be regarded as having the rights of a child and in effect cleared IVF disposal of surplus embryos.
Mitochondrial donation also sets off ethical alarm bells among those who say that it breaches the until-now taboo prohibition on tampering with the germline – changing the genetic inheritance of subsequent generations. This is true in that the technique removes from later generations the danger of having faulty mitochondria, although it does not affect the inherited DNA in the nucleus which shapes the individual character and traits of recipients.
Legislative duty
But if it is okay to repair faulty mitochondria, the slippery slope argument goes, what about other genetic diseases caused by faults in nuclear DNA? And if you cross this line, ostensibly for fine medical reasons, then surely it becomes easier to move towards “designer babies” whose genes are manipulated to select preferred traits?
Easier, perhaps, but not necessary – hence the need belatedly for the political class to do its legislative duty to provide a proper framework that would set the limits of research and clinical practice.
The Commission on Assisted Human Reproduction 10 years ago called for legislation and Mr Justice Adrian Hardiman recently berated politicians’ legislative inertia as akin to a situation where “road traffic law had failed to reflect the advent of the motor car”.
Despite the relief that mitochondrial donation could bring to many women, however, the prospects for acknowledging the motor car’s arrival do not look good. psmyth@irishtimes.com