Human Genome Editing: From the First to the Third International Summit

Françoise Baylis discusses the outcome of the Third International Summit on Human Genome Editing.


In early March, I was in London, England for the Third International Summit on Human Genome Editing. It was a welcome occasion to see friends and colleagues and to advance discussion and debate on research involving somatic, germline, and heritable human genome editing.

Somatic human genome editing involves the genetic modification of somatic (nonreproductive) cells. Changes made to these cells are not passed on to subsequent generations. Germline human genome editing involves the genetic modification of reproductive cells (eggs and sperm) or early stage (one-cell) embryos. This research occurs in the lab and when the research is done the modified cells are discarded. Heritable human genome editing involves the transfer of genetically modified reproductive cells to a uterus in the hope of creating genetically modified children.

In this brief commentary, I share my reflections on two of the many successes of the Third International Summit: (1) increased focus on the science, ethics, and governance of somatic human genome editing and (2) public acknowledgment of the need for further discussion and debate about “whether” to proceed with heritable human genome editing.

Photo Credit: T/flickr. Image Description: Monument to the laboratory mouse, a mouse knitting a DNA strand behind the Institute of Cytology and Genetics.

This Summit, unlike the previous two Summits, intentionally focused attention on the science, ethics, and governance of “in progress or soon to be initiated” clinical trials involving patients with genetic disease. This focus was evident not only in the design of the program, but also in the Closing Statement issued by the Organising Committee. The Statement highlighted the remarkable progress that has been made in recent years toward the laudable goal of curing “once incurable diseases”. It also underlined the problem of catastrophic pricing which, if left unchecked, would effectively ensure that the benefits of science would not make it from bench to bedside. The Organizing Committee issued a clarion call for affordable, equitable access to gene-based treatments.

As concerns heritable human genome editing, the Closing Statement, consistent with other recent international documents, stipulated that “Heritable human genome editing remains unacceptable at this time.” The Organizing Committee went further, however, to explicitly acknowledge that “Public discussions and policy debates continue and are important for resolving whether this technology should be used.” (emphasis added) Examined in the context of previous Summit Statements this sentence signals an important shift.

For context …

In the Spring of 2015, duelling commentaries on the ethics of heritable human genome editing were published in the journals Nature and Science. Shortly thereafter, the first science paper on germline genome editing was published in the journal Protein and Cell. This paper described the genetic modification of the gene responsible for β-thalassaemia in non-viable human embryos using CRISPR/Cas9. Following on these publications, the First International Summit on Human Gene Editing was held in Washington in December 2015.

The Closing Statement for the First Summit stipulated that, “It would be irresponsible to proceed with any clinical use of germline editing unless and until (i) the relevant safety and efficacy issues have been resolved, based on appropriate understanding and balancing of risks, potential benefits, and alternatives, and (ii) there is broad societal consensus about the appropriateness of the proposed application.”

Fast forward to November 2018 and the Second International Summit on Human Genome Editing in Hong Kong. Immediately prior to the start of this meeting, Jiankui He announced that he had used CRISPR/Cas9 to edit the CCR5 gene in human embryos to create children with resistance of HIV. This research, unlike the previously reported research by Huang, involved the genetic modification of viable embryos and the transfer of these embryos to a uterus for gestation. To be clear, the science that prompted the First International Summit involved germline human genome editing.  The science that hijacked the Second International Summit involved heritable human genome editing.

While Jiankui He’s experiment was almost universally condemned, this condemnation did not translate into a forceful endorsement of the pre-requisites for heritable germline genome editing issued in 2015. Instead, there was a pendulum swing in support of science aimed at addressing the “how” of heritable human genome editing. The Closing Statement for the Second Summit announced that while it was premature to move forward with clinical trials involving pregnancy it was “time to define a rigorous, responsible translational pathway toward such trials.”

With the Closing Statement from the Third International Summit the pendulum has swung back insofar as the importance of paying attention to the “whether” (not just the “how”) of heritable genome editing is acknowledged.

As a long-standing proponent of broad societal consensus, I hope that this recent swing will encourage discussion and debate aimed at consensus-building. This is not to presume that broad societal consensus will be achieved. This may prove unattainable. As I have said on many occasions, however, we will all be the better off for having tried to reach consensus.


Françoise Baylis is Distinguished Research Professor Emerita at Dalhousie University. She is the author of Altered Inheritance: CRISPR and the Ethics of Human Genome Editing.  She was a member of the Organizing Committee for the First and the Third International Summits @FrancoiseBaylis

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