Patrick Foong, PhD
Western Sydney University
Sydney, NSW, Australia
Three leading scientific and advocacy societies have called for a continued international 10-year moratorium on heritable human genome editing (HHGE). The position paper was led by the International Society for Cell and Gene Therapy (ISCT), the Alliance for Regenerative Medicine (ARM), and the American Society for Gene and Cell Therapy (ASGCT).
During the Second International Summit on Human Genome Editing in 2018, Dr. He Jiankui claimed that twin girls, Lulu and Nana, had their genomes modified by the CRISPR technology to confer their resistance to HIV, the virus that could lead to AIDS. The world, especially the scientific community, reacted with shock to the announcement.
The groups compared heritable editing with recent improvements in somatic cell gene therapies, where FDA-approved therapies are offered for genetic conditions such as sickle cell disease and beta thalassemia. These therapies modify DNA in the patient’s non-reproductive cells in order to treat genetic diseases. It is imperative that there is a responsible use of gene innovation and premature ventures must not undermine these advancements into HHGE. The moratorium targets HHGE as it involves changing early embryos, eggs or sperm and passing genetic changes to the next generations. In contrast, somatic cell gene editing (SCGE), which alters a patient’s DNA in non-reproductive cells, cannot be inherited by subsequent generations.
In theory, HHGE could also edit genes to create designer babies or enhancements, and this is not even related to a disease or condition. Germline modification could enable couples to enhance certain characteristics of their children. CRISPR could be used to edit the human genome to select for specific traits, such as athleticism or intelligence. The genes could be altered, including the removal of undesired traits or the insertion of desirable ones. Germline changes could meet future needs to design individuals to appear more attractive, have a higher IQ, or be an Olympian.
Currently, there is a questionable medical need for HHGE, as several alternatives exist that do not involve heritable genetic modifications. Couples who are concerned about transmitting severe genetic diseases to their offspring currently already have other safer and more established alternatives, e.g. preimplantation genetic testing (PGT), prenatal testing and gamete donors.
Moreover, there are long-term risks with embryo and gamete editing compared to somatic editing. The development of CRISPR is under scrutiny and safety is a main concern. Although this technology improved upon the older methods, it is far from perfect. For example, it is possible to cut at the wrong spot, known as off-target effects, where edits are performed in the incorrect area, and scientists are uncertain about how this could affect the individual. The other issue is mosaicism, where only some of the cells carry the edit but not others. It is not noted that these risks could affect not only the individual born from an edited germline but also their offspring. Moreover, they could have irreversible effects on the person born from edited germlines and their subsequent generations.
Evaluating the safety of gene therapies and improving genome editing technologies are vital steps to ensure that CRISPR is ready for human application. By pursuing fundamental research, genome editing can ultimately be deemed safe and effective. Currently, multiple studies are focused on addressing this crucial issue.
[1] https://www.isct-cytotherapy.org/article/S1465-3249(25)00718-2/fulltext
[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC6813942/
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