Experts from the European Society of Human Genetics (ESHG) warned that checking embryos using a polygenic risk score (PRS) may give a result that is “dangerously incomplete and can lead to grave misunderstandings”.
They said there is no evidence the test can accurately predict the chances that a baby will go on to develop a range of conditions, as some firms claim, such as diabetes, heart disease, cancer, stroke, schizophrenia and Alzheimer’s.
The main problem is there are institutions that sell these tests to parents, with the hope that this can … select better embryos, or designer babies
Using a PRS for embryo screening is not currently allowed in the UK, though it is being piloted on the NHS to screen for heart disease risk among adults.
Experts are concerned that couples may be attracted to seeking out a PRS in the US or parts of Europe, with one saying that marketing PRSs for use in embryos is like “selling snake oil”.
To date, at least one child has been born after PRS embryo screening but, writing in the European Journal of Human Genetics, the experts said: “The utility of a PRS in this respect is severely limited, and to date, no clinical research has been performed to assess its diagnostic effectiveness in embryos.”
There are concerns PRSs could be used to screen for things like height and intelligence, with the experts saying a “societal debate, focused on what would be considered acceptable with regard to the selection of individual traits, should take place before any further implementation of the technique in this population.”
In its paper, the team argued that a child’s chances of developing an illness is often a complex interplay of many genes, together with environmental factors, nutrition and exercise.
“No clinical research protocol has been performed so far to assess the diagnostic effectiveness of PRSs in embryos,” they said.
“Were these to be established, it would take many years to obtain reliable results, given that one might have to wait decades for people to develop, for example, early-onset Alzheimer’s disease.”
Many conditions are caused by a combination of genetics and environment
Professor Maurizio Genuardi, president of the ESHG, told a UK media briefing: “We believe that this is a highly promising field in genetics and also for prevention of disease but, at the current stage, it cannot be used.
“The main problem is there are institutions that sell these tests to parents with the hope that this can be helpful to select better embryos – or designer babies – but the information that is provided is not accurate. It is incomplete.”
Prof Genuardi said couples offered a PRS were paying for something “that has no value based on current knowledge”, and said “the hope to have better babies is a misleading advertisement.”
He added: “There is no evidence that this kind of selection can lead to a better or healthier baby.”
Professor Markus Perola, a consultant in public health medicine and senior lecturer in quantitative genetics at the University of Helsinki, said PRSs are “impossible to use for embryo selection”, adding that “if you sell this kind of thing, I would say that you are selling snake oil.”
He said PRSs are an “interesting piece of genetic work that might have some clinical implications,” but added that for embryo selection, they are “unusable, unethical and impractical.”
Dr Francesca Forzano, consultant in clinical genetics from Guy’s & St Thomas’ NHS Foundation Trust, said PRSs for embryos are offered largely in the US but we “do not really have a very good sense of what is happening in each individual private clinic across Europe and other countries as well.”
(The Progress Educational Trust) supports this clear and unequivocal warning to fertility patients not to waste their money on having embryos tested using polygenic risk scores. The tests have no clinical validity
She added: “This is mostly an American offer but we are also wary that, when it is a matter of private practice, and also direct to consumer testing, this does not necessarily mean that European customers … might be completely out of the game … ”
She said that, with other types of testing, patients can simply “ship a sample”.
Genetic testing on embryos, which can include preimplantation genetic diagnosis (PGD), is available in the UK for specific conditions such as cystic fibrosis.
Dr Forzano said: “In these cases, the disease has a single genetic cause and therefore the ability of the test to predict its development in any offspring is high.
“PRSs are a completely different matter. Many conditions are caused by a combination of genetics and environment and PRSs are only able to capture parts of any of the relevant genetic component, which is itself likely to be highly complex and difficult to analyse.”
Asked about PRSs, Peter Thompson, chief executive of the Human Fertilisation and Embryology Authority (HFEA), said in an earlier interview with The Observer “there is an important distinction between embryo selection to avoid serious harm and for so-called ‘enhancement’, like greater intelligence.
“The latter would represent a fundamental public policy shift.”
The use of polygenic risk scores in pre-implantation genetic testing is currently illegal in the UK. Embryo selection is only legal in the UK to avoid serious inherited illnesses
Sarah Norcross, director of the Progress Educational Trust (PET) charity, said the tests are not ethical, adding: “PET supports this clear and unequivocal warning to fertility patients not to waste their money on having embryos tested using polygenic risk scores.
“The tests have no clinical validity.
“The Human Fertilisation and Embryology Authority (HFEA) should clarify the legal and regulatory status of such tests within the UK, while the Advertising Standards Authority and the Competition and Markets Authority should keep a careful eye on whether and how such tests are marketed to UK patients.
“Fertility clinics should not be offering these tests.”
The HFEA said in a statement: “The use of polygenic risk scores in pre-implantation genetic testing is currently illegal in the UK.
“Embryo selection is only legal in the UK to avoid serious inherited illnesses, usually by means of pre-implantation genetic diagnosis authorised by the HFEA, known as PGT-M or PGT-SR.
“There is no scientific consensus that it is currently possible to test and identify genes for complex traits. Before this could be introduced into UK law it would need a shift in public policy, and a range of ethical concerns to be addressed, which would require Parliamentary approval and the backing of society more generally.”