Parents can now have a baby with three sets of DNA, or they might be able to in five years if researchers from Newcastle University are successful in lobbying on behalf of a new procedure. A method has been found that will allow parents to transplant healthy mitochondria from a donor to replace a mother’s faulty mitochondria. The process is known as three-parent-invitro-fertilization (IVF) and it will prevent a number of hereditary diseases associated with faulty mitochondria from developing in newborns.
The procedure is currently illegal in all countries, but researchers in the UK are lobbying for its legality. In response, the British government has begun public hearings on the topic of three-parentIVF in order to educate the public about the issue and to gauge public support its legalization.
The legalization of three-parent IVF is a contentious issue because of the moral questions associated with it. Nick Collins of The Telegraph quotes Lisa Jardine, chair of the Human Fertilisation and Embryology Authority (HFEA), as identifying the key issue at stake.
She said, “We find ourselves in unchartered territory, balancing the desire to help families have healthy children with the possible impact on the children themselves and wider society.”
The three-parent IVF process
There are two procedures for transferring healthy mitochondria.
The first is known as pro-nuclear transfer (PNT). It works by transferring both the pronuclei from the mother and the pronuclei from the father into a donor embryo that has healthy mitochondria (with its own pronuclei removed).
The second method is known as maternal spindle transfer (MST). The maternal spindle is a subcellular structure that is found inside the egg and contains the mother’s DNA. During the MSTprocedure, the spindle is removed from the mother’s egg and put inside the donor egg. It is then fertilized by the male’s sperm.
In both cases, the fertilized egg develops as it normally would; except that the mother’s mitochondrial DNA has been replaced with that of the donor. This means that the embryo will develop with three sets of DNA which can potentially be passed onto future generations.
It should be noted, however, that mitochondria have no effect on the genetic makeup of the embryo (i.e. hair colour, height, eye colour etc.). The purpose of the mitochondria is to power the rest of the cell. In this way, they can be regarded as the cell’s battery.
The greater debate
Dr. Kerry Bowman, a clinical ethicist at the University of Toronto’s Joint Centre for Bioethics, has identified the key bioethical question as being, “Are we crossing a line that should not be crossed?”
While Dr. Bowman was unable to come up with a definitive answer himself, simply stating that to some extent we are, he did say that navigating the issue required a “risk-benefit equation.”
For those in favor of legalizing three-parent IVF, the obvious good is in permanently removing a genetic mutation that will alleviate the suffering of future generations.
Around one in every 6500 children born worldwide are afflicted with a disease associated with damaged mitochondria.
The primary health risks that arise from faulty mitochondria are dystrophy and mitochondrial myopathy, though there are a host of less common risks, such as diabetes mellitus deafness. By legalizing the procedure, scientists would be able to eliminate these sorts of degenerative diseases from the genetic code.
Symptoms that are associated with mitochondrial diseases usually result in muscle weakness, loss of coordination, learning disabilities, organ disease (such as heart, liver, kidney etc.) and neurological disorders.
Dr. Bowman claims that there is an, “ethical merit” to stopping mitochondrial diseases and ending the potential suffering that those afflicted with the condition may have, but also that there are unknown risks associated with the procedure.
Since the transplanted mitochondria has DNA of its own, this third party DNA will be passed down, and this is where the major ethical dilemma begins, as scientists are not sure how this will affect future generations.
Jardine told The Telegraph that, “this is not about our children. It’s not even about our grandchildren. It’s about many generations down the line what the consequences might be.”
But the unknown risks are not the only major dilemma surrounding three-parent IVF.
Also at issue are questions of identity, third party rights and the slippery slope argument.
When asked if he thought three-parent IVF would affect the status of identity Dr. Bowman replied, “I would agree that it does,” stressing that some genetic material from the donor is passed on.
He went on to identify that the child at some point may ask to meet the third party donor and he posed the question of whether or not the third party donor is a parent.
However, three-parent IVF would allow parents who want to have a genetically related child without mitochondrial disease to do so.
Reuters quotes George Watts, who chaired an inquiry by Nuffield into the issue, as identifying this point. He then went on to say that, “the descendants of any woman born via these therapies should inherit healthy mitochondria and be free of mitochondrial disorders.”
Dr. Marita Pohlschmidt, of the Muscular Dystrophy campaign, told The Telegraph, “For women who have been dealt the heavy blow of living with mitochondrial disease, the prospect of bearing healthy children is of immeasurable value. We believe that this technique could open up the possibility of motherhood untainted by the fear of passing on a painful, debilitating condition to their future children.”
However, the benefits of three-parent IVF must be weighed carefully against what is known as the slippery-slope argument.
There are concerns that if three-parent IVF treatment is legalized, it will pave the way for other more extreme germline therapies and manipulations, namely the creation designer babies.
Shawn Winsor, an Ethicist with the University of Toronto’s Joint Centre for Bioethics recently spoke with CTV News. He told them, “Do we want to take the chances with slippery slope implications for a tiny group of people? That’s something I think the public needs to weigh in on.”
However, it is also important to note that swapping the mitochondria in three-parent IVF is not the same as actively manipulating the DNA in the cell’s nucleus and that legalizing three-parent IVF does not necessitate the legalization of actively manipulating the cell’s nucleus. Such a procedure would require its own separate legislation.
The way forward
It is hopeful that the public consultations in Britain will answer a lot of these difficult moral questions and gauge how the public feels about three-parent IVF. It should be noted, however, that since these are public consultations where just about anyone is free to participate, there is also the potential that they may be derailed by groups that have a specific agenda in mind, whether it be conservative or liberal in nature.
Nevertheless, the scientific community is looking forward to these consultations.
Sharmila Nebhrajani, head of Britain’s Association of Medical Research Charities told the Vancouver Sun that, “This is our chance to have a thoughtful and insightful discussion about the issues, benefits and risks of these techniques and … make an informed decision about techniques that could yield an answer for some debilitating and currently incurable diseases.”
Dr. Bowman stated that there is, “strong reason[s] to do the treatment” but also cautioned that, “genetic identity is extremely important in the 21st century.”
As such, we return to the cost-benefit equation.
In a separate interview, Dr. Bowman is quoted by Yahoo News as stating that, “As we understand it right now, it appears that the benefits outweigh the potential harm or risk.”
However, this might change once the results of the UK’s public consultations are known. The HFEAhas used public consultations previously to gauge public support for bioethical issues, such as the case for parents being able to choose the sex of their baby or the use of other germline manipulations.
When the first IVF baby was born in 1978, the public had generally mixed feelings about it. Jardine is quoted by The Independent as saying that, “the day Louise Brown was born…was uncharted territory. Many thought she would turn out to be a monster. Those uncharted waters are now charted – IVF is now routine.”