Where does the world stand on designer babies? An international report released in September 2020 advises that heritable genome editing is not yet ready to be tried safely and effectively in humans.
It cites that initial clinical uses, if permitted, should be limited to serious single-gene diseases where it is known, with strong evidence, that a specific mutation is causing the disease. Wits Professor of Human Genetics Michèle Ramsay, who is also the Director of the Sydney Brenner Institute for Molecular Bioscience in the Faculty of Health Sciences contributed to this report on Heritable Human Genome Editing.
What is heritable genome editing?
Heritable genome editing refers to the use of techniques that edit or alter genetic material (DNA) in a human germ cell or early embryo, resulting in changes in the germline (sperm and egg cells) – which means that the changes in the DNA can be passed onto the offspring through the genetic material.
Because clinical applications of germline genome editing are now possible, albeit not yet with sufficient accuracy, there is an urgent need to examine the potential of this new technology. However, the implications of how heritable human genome editing might affect future generations is not yet fully understood and needs to be the topic of wide debate.
“Making edits to the human genome that will be passed on from generation to generation is a very big step. We have a responsibility to society and future generations to approach this with great caution and long deliberation,” says Ramsay, who participated in the conversations when Wits University hosted the first South African Gene Editing Conference in November 2019.
Where are the ethical boundaries in this futuristic field?
Heritable human genome editing poses many ethical questions, because a gene or DNA sequence should not be used to create a pregnancy until it is established that precise genomic changes can be made reliably, without introducing undesired changes — a criterion that has not yet been met by any genome editing technology, says the report.
It concludes that should human genome editing technology advance according to specific criteria and should a country decide that it was desirable — neither of which has happened so far — proposed first-in-human cases would need to fulfil four criteria:
- Edits should aim to correct a mutation for a serious monogenic disease.
- The edited change should be to a sequence that is common in a population and should not be known to cause diseases.
- No embryos that are unaffected by the mutation should be edited.
- The technology should be available only to couples with no or very poor options for having their own biological child without a serious genetic disease.
It is not yet possible to define responsible translational pathways from research to clinical application for other potential uses of heritable human genome editing. However, the technology could potentially be used for less serious monogenic diseases or for enhancing certain traits where it is known that a single mutation is strongly correlated with the trait.
“[But] using the technology for complex diseases such as diabetes, hypertension and most cancers would be much more complicated, as they involve thousands of variants and are influenced by non-genetic factors, such that at present it is not possible to predict the outcomes. International co-operation and open discussion of all aspects of heritable genome editing will be essential,” concludes Ramsay.