The Californian company MyOme has claimed to be able to decipher almost the entire DNA code of a day-old embryo created by in vitro fertilization (IVF), by sequencing the DNA of both parents and “reconstructing” an embryo’s genome using that data.
From these results it is inferred that it could be plausible to estimate the risk of diseases that could arise decades later in the individual simply by observing an embryo created by IVF with only a few days of age.
The application of technology to IVF embryos has generated quite a bit of controversy among scientists as the bioethics of genetically modified children could be incredibly dangerous or delicate, according to different scientific opinions.
According to their work, which has been published in the journal Nature Medicine, the researchers used data collected during the IVF process, as 110 embryos from the couples had undergone limited genetic testing at the time. They claimed to have achieved the scores by sequencing the genomes of 10 pairs of parents who had already undergone IVF and had children.
Using population genomics and statistical tools, the experts were able to anticipate a large amount of embryonic DNA (96% in a 3-day embryo and 98% in a 5-day embryo) by combining this data with the genomic sequences more complete parents.
The method described in Nature also allows polygenetic testing for 12 common diseases . They were able to calculate the risk of breast cancer, type 2 diabetes, or coronary artery disease (CAD), for the embryos.
ethical issues
It is clear that new technologies are expanding the scope and accessibility of preimplantation genetic testing of human embryos. But what these advances can bring us may not yet be clear. Over time, this technology will become a challenge come true for countless doctors and patients.
It is positive to want to avoid transmitting a high risk of disease to offspring, but should we use these techniques to detect embryos that are going to have greater educational success, for example? It could change everything if we could select embryos based on their IQ or traits.
In fact, authors Josephine Johnston, director of research at The Hastings Center, and Lucas J. Matthews, a professor at Columbia University, cite several ethical questions about the use of the polygenic risk score, or PRS, (which combines the effects of many genetic variants with small individual effects on a single risk estimate):
- The polygenic risk score shows limited predictive accuracy in populations of non-European descent.
- Patients may not fully understand the risks and limitations of the tests
- Expanded genetic testing, such as the existing preimplantation genetic testing used to identify embryos with or without specific genes, could be labeled discriminatory because they involve the selection of embryos based on genetic risks for specific diseases, disabilities, or traits.
For its part, the European Society of Human Genetics considers the use of polygenic values to select human embryos neither proven nor ethical. ESHG stands firm and against the use of polygenic risk values to select human embryos.
Referencia: Kumar, A., Im, K., Banjevic, M. et al. Whole-genome risk prediction of common diseases in human preimplantation embryos. Nat Med 28, 513–516 (2022). https://doi.org/10.1038/s41591-022-01735-0
Forzano, F., Antonova, O., Clarke, A. et al. The use of polygenic risk scores in pre-implantation genetic testing: an unproven, unethical practice. Eur J Hum Genet (2021). https://doi.org/10.1038/s41431-021-01000-x
