A form of genetic testing offered by some private fertility clinics does not have scientific basis to support its use. This is according to a committee chaired by one of our researchers.
Dr Francesca Forzano is consultant in clinical genetics at Guy’s and St Thomas’ and chair of the European Society of Human Genetics Public and Professional Policy Committee. A paper published in the Society’s journal outlines the lack of evidence to support testing for conditions caused by multiple genes. The testing is available in some private clinics, but it is not currently available on the NHS.
Other types of genetic testing are currently used at both NHS and private fertility clinics. These check embryos for chromosome anomalies, or certain single gene related conditions. In these cases, the ability of the test to predict the development of the disease in any offspring is high.
However, the type of testing examined in the paper looks at diseases where several genes are involved. This type of testing is called ‘polygenic risk scores’.
The paper by the Committee outlines that there is no evidence that polygenic risk scores can predict whether children will develop a specific disease.
It argues that private fertility clinics providing this type of testing raises many concerns. The form of testing is not provided within the NHS due to the lack of evidence for clinical benefit.
Dr Francesca Forzano said: “Many conditions are caused by a complex combination of genetics and environment, and polygenic risk scores are only able to capture parts of the relevant genetic component. And when applied to selecting embryos for transfer in IVF, the score will relate to an individual family rather than to a wide population, and therefore will not be very useful in determining the choice of one embryo over another.”
Polygenic risk scores have never undergone clinical trials to test their use in embryo selection. Instead, research on genetic risk aims to help understand how diseases work. Genetic research can also help to suggest new ways to treat conditions.
The paper argues that performing a polygenic risk score test for embryo selection would be premature at best. It says that information on the risks and limitations of the practice should be provided to prospective parents and the public.
The authors call for a public debate to take place before any potential application of the technique in embryo selection. Such a debate should focus on what would be acceptable in selecting individual traits. Without proper public engagement and oversight, implementing polygenic risk score tests for embryo selection could lead to the stigmatisation of certain conditions.
Professor Maurizio Genuardi, ESHG President said: “It is also vital to provide prospective parents with a clear understanding of the difference between counselling and marketing. And at a time when healthcare resources are under strain, it is important that the limited money available should be spent on tests that are known to be effective. Currently, research resources would be better spent on improving knowledge about how polygenic risk scores interact with the environment in which we live, rather on the premature application to our future children of an inadequately assessed test with potentially misleading results.”
