Preimplantation Genetic Diagnosis
Monitoring system for health and social effects recommended
The Human Genome Research Project has reported positively on the use of a technique that allows implant embryos to be
screened for genetic disorders.
The New Zealand Law Foundation-sponsored project, led by ProfessorMark Henaghan, Dean of the Faculty of Law at the
University of Otago, finds that though Preimplantation Genetic Diagnosis (PGD) is not yet widely used, data from PGD
centres leads to the conclusion that it is medically safe.
“PGD is seen by some as the beginning of a slippery slope towards designing the perfect baby, but in reality the
procedure cannot be used to screen for intelligence or physical attributes - in other words, it cannot be used to
improve or modify embryos," he says.
"However it can be used to screen for embryos with severe inherited genetic disorders, such as cystic fibrosis, so they
can be removed from the pool of embryos available for transfer."
Choosing Genes for Future Children: Regulating Preimplantation Genetic Diagnosis, is the first major report from the
three-year multidisciplinary project which draws together a team of New Zealand and international researchers in Law,
Bioethics, Science, Mäori and Paediatrics to examine whether, how and to what extent, human genome-based technologies
should be regulated.
The more-than-350-page report was released at a function at Parliament today (Tuesday 1 August).
PGD became publicly funded by the New Zealand Government this year. The technique involves creating embryos outside the
mother and testing them for genetic disorders, such as Huntington's disease, before implanting them.
The report outlines the clinical history and use of PGD and then goes on to examine and question ethical, legal and
regulatory issues surrounding its use, as well as address Mäori cultural perspectives.
The report analyses three major ethical objections to the use of PGD - the destruction of embryos, 'playing God' and
concerns about eugenics.
"I think the report recognises the range of ethical viewpoints," says Professor Henaghan. "In the end it also recognises
that modern medicine intervenes in human life in many areas to ease suffering."
Effort has also been put into addressing Mäori values and beliefs surrounding the use of PGD technology, with in-depth
interviews with a range of Mäori participants.
"While no single Mäori view emerged on the potential risks and benefits of PGD, we did see strong patterns emerge,
including a general agreement that this technology has the potential to do more good than harm for Mäori communities,"
he says. "The main concern was that Mäori may not have equality of access to PGD."
Prof Henaghan says the report raises questions about the current controls on the use of PGD. For example, it questions
whether the outright ban on the non-medical sex selection is too rigid.
It also highlights inconsistencies in the current regulation of PGD. "An example of this is the way the selection of
embryos for a genetic impairment seen in a parent is prohibited. For example, deaf parents may not select an embryo that
carries the genetic mutation that encodes for deafness, even when the parents consider that deafness is not an
‘impairment’ but rather a disorder that can be life-enhancing" says Professor Henaghan.
"Such a prohibition may also present difficulties for parents where there is limited or a lack of suitable embryos for
implantation. These examples are inconsistent with prenatal testing where parents can choose to continue with a
pregnancy even though they have been made aware of a genetic impairment in a foetus."
These inconsistencies also extend to so-called 'saviour siblings' - where a child with a severe life-threatening
condition can be saved if a sibling is born with compatible genetic tissue, says Prof Henaghan.
"PGD can be used to test for compatibility but only when the sick child has a familial genetic disorder - one which has
been passed from parent to child. If the condition is non-heritable then PGD cannot be used," he says. "This anomaly
could be addressed by a allowing the use of PGD to create a 'saviour sibling' in cases where the child is suffering from
a severe life-threatening condition whether familial or not."
Prof Henaghan says that overall the report finds the current uses of PGD do more good than harm."We do recommend that a
system be put in place to monitor the health and social outcomes of the ongoing use of PGD."
The New Zealand Law Foundation-funded Human Genome Research Project will now broaden its work to examine questions about
genetics and society, involving whole genome screening technology and genetic testing of newborns and children.
Summary of main findings:
(a) PGD is not yet a widely used procedure. Data from the world’s three largest PGD centres comprising 4748 PGD
attempts and 754 successful pregnancies led to the conclusion that PGD is medically safe for the mother and the
resultant child. Currently, however, there is no data on the health of PGD children as they grow older.
(b) PGD cannot be used to screen for intelligence or other physical attributes such as looks and height. PGD cannot
be used to improve embryos or modify them. Current usage is negative selection whereby the seriously affected embryos
are removed from the pool of embryos available for transfer. It is not selection of genetically elite embryos. It can be
used to screen for severe inherited genetic disorders such as cystic fibrosis.
(c) The question of whether or not New Zealand develops full capability for PGD depends on the actual and projected
update by the population. PGD is a highly specialised technique and requires skilled personnel.
(d) The report analyses the three major ethical objections to the use of PGD – the destruction of embryos, ‘playing
God’ and the eugenic concern of eliminating certain disorders - and finds that there is a wide range of views on the
ethical objections.
In addressing these concerns the report settles on a gradualist approach to the human embryo that the embryo is more
than a mere collection of cells but less than a full person. It finds that modern medicine intervenes in human life in
many areas to avoid agonies being suffered by people. In the same way, PGD can be used to avail the intractable and
unbearable suffering brought about by serious incurable genetic disorders.
Eugenics is generally associated with state-enforced programmes that impose a genetic blueprint. PGD is used by a small
number of intending parents exercising individual choices to avoid serious, incurable genetic disorders in their
families. The New Zealand Organisation for Rare Disorders is open to the use of PGD.
(e) General agreement was found from Maori perspectives that PGD has the potential to do more good than harm for
Maori communities. As one Maori participant in the study said:
“If there is the power to change it, would you? If you knew that your child was going to have a terminal disease that
would kill them by the age of two or three and be in absolute pain and agony for that two or three years. If I had had
that choice, I wouldn’t want to see anybody go through that pain, child or not.”
There is concern that Maori may not have equality of access to PGD.
(f) Currently, PGD is an ‘established procedure’ in New Zealand with guidelines dictating its use. ‘Serious
impairment’ is the basis for the general use of PGD which would include late onset conditions such as breast cancer
which can be identified at the preimplantation stage. Non-medical sex selection is banned outright and the report
questions whether this is too rigid a stance given that public and other attitudes can shift rapidly. For example in
Scotland, the Masterton family tragically lost their only daughter in an accident. They had four sons and wanted another
daughter. A ban on sex selection in the UK forced them to go to the USA where there is no such ban.
(g) The research report highlights inconsistencies in the current regulation of PGD. For example, in relation to
preimplantation, selecting embryos for a genetic impairment seen in a parent is prohibited. This is inconsistent with
prenatal testing where parents can choose to continue with pregnancy when aware of genetic impairment in a foetus.
(h) A child with a severe life-threatening condition can be saved by a sibling, if the sibling is born with
compatible genetic tissue. PGD can be used to test embryos for a sibling with compatible genetic tissue. At present, PGD
can only be used in this way when the sick child has a familial genetic disorder (a familial condition is passed from
parent to child; ‘familial’ denotes that the disorder tends to occur in more members of a family than expected by chance
alone). If the sick child is suffering from a non-heritable condition (a condition not present in a parent or other
family members but which manifests in the child), then PGD cannot be used. In both cases, the child is very sick. For
example, if child A suffers from a serious familial anaemic condition, then a ‘saviour sibling’ can be created. If child
B suffers from a serious anaemic condition which is not familial (not passed from the parent to the child), a ‘saviour
sibling’ cannot be created. The anomaly could be rectified by allowing for the use of PGD to create a ‘saviour sibling’
where the affected child is suffering from a severe life-threatening condition whether familial or not.
(i) Overall the report finds that the current uses of PGD do more good than harm. The report recommends that a
monitoring system be put in place to keep track of the health and social outcomes of the ongoing use of PGD.
Human Genome Research Project Investigators at the Otago University include:
- Professor Mark Henaghan, Dean of the Faculty of Law
- Professor Donald Evans, Director of the Bioethics Centre
- Professor Stephen Robertson, Paediatrics and Child Health, Department of Women’s and Children’s Health
- Dr Ian Morison, Biochemistry Department
External collaborators:
- Bevan Tipene-Matua, Kaiarahi – Executive Director (Mori), Te Wanaka o Otautahi Christchurch Polytechnic Institute of
Technology
- Professor Sheila McLean, Director, Institute of Law and Ethics in Medicine, University of Glasgow, UK
- Associate Professor Mildred Cho, Associate Director, Stanford Centre for Biomedical Ethics, Stanford University, USA
Ends