The use of DNA chip (microarray) technology in embryo screening is to be investigated by an ethics task force from the European Society of Human Reproduction and Embryology (ESHRE). The technology has the potential to screen IVF embryos, in order to improve fertility treatment success rates. In addition, it may be possible to screen embryos for chromosomal abnormalities, and for genetic variations that could cause disease.
Professor Guido De Wert, the chair of the task force, has launched a consultation process with ten European fertility centres. The aim of the ESHRE task force is to assess how advanced the microarray technique is, its potential use for embryo screening and, ultimately, develop a code of practice to regulate its use.
Microarrays can identify the presence of thousands of genetic and chromosomal abnormalities in a sample of DNA. This may allow embryos with the best chance of implantation in IVF to be selected. Another implication is that it may be possible to identify if an embryo has genetic variants that could pre-dispose it to disease later in life, such as diabetes or heart disease. However, such diseases are complex, and the clinical significance of many genetic variations is unknown. Professor De Wert said that 'one of my concerns is that people who are naive about genetics think that it is easy to pick the best embryo. But even the best geneticists don't know how to interpret how diseases might develop from gene chip information'. Professor De Wert also said that this technique should only be used to improve IVF treatment.
The British Fertility Society recently issued guidelines advising against the use of PGS (preimplantation genetic screening), where embryos are screened for chromosomal abnormalities. This is different from the use of PGD. Currently in Britain clinics have to apply to the Human Fertilisation and Embryology Authority each time they want to test for a new genetic disorder. Microarrays may allow all tests to be carried out at the same time, requiring new sets of guidelines. The ethics task force will help to shape such guidelines for good clinical practice, and help determine what it is appropriate to screen embryos for.