This is not without problems, as illustrated by the cautionary tale of Chinese geneticist He Jiankui. In 2018, He announced that he had used the CRISPR gene editor to alter the DNA of human embryos to make them less susceptible to HIV. The birth of these first edited children caused an international outcry. He was sentenced to prison and the incident thrust the capabilities of CRISPR, only discovered 6 years earlier, onto the world stage.
He’s work was met with international repudiation because it affected the germline (and thus those children’s future children) before full safety had been demonstrated. However, powerful techniques are now emerging that could soon make direct edits to hard tissue without being passed to future generations, or even that make germline edits safer. The same pathway He edited in the twins is involved in resistance to several diseases such as dengue, yellow fever, and West Nile virus. The promise is clear. But it is also clear that this work must be done under international oversight.
To bring in vivo genome editing into the mainstream, gene editors need to become more precise, less toxic and create fewer side effects, unintentional alterations, and immune reactions. This requires not only a better understanding of the links between gene networks and disorders, but more targeted ways to deliver the editor into tissues that are hard to reach, including novel viral and chemical methods and techniques from synthetic biology.
Selection of GESDA best reads and further key reports:
In 2017, Weisberg et al surveyed a large and diverse cohort of Americans about their attitudes to genetically modify human germlines; the results make fascinating reading.1 An international commission of the U.S. National Academy of Medicine, U.S. National Academy of Sciences, and the U.K.'s Royal Society, “Heritable Human Genome Editing” considers potential benefits, harms, and uncertainties associated with genome editing technologies.2 In 2019, the WHO Expert Advisory Committee on Developing Global Standards for Governance and Oversight of Human Genome Editing issued a useful background paper: “The Ethics of Human Genome Editing”3 A useful overview of non-germline research can be found in the NIH publication “The NIH Somatic Cell Genome Editing program”.4 In July 2021, WHO published “Human Genome Editing: Recommendations”.5