The (at least, an) other side of the argument about heritable human gene editing

By Jon Holmlund

Last week’s New England Journal of Medicine (subscription required) included four articles addressing heritable human gene editing (HHGE, if you’ll allow the acronym).  All assumed that it would or should go forward, under oversight, rather than seeking a moratorium.  One took the position that a moratorium is a bad idea, because the “rogues” would press ahead anyway, and the opportunity to create meaningful partial barriers to at least slow down what could easily be a runaway train.

This week, a group of prominent scientists in the field, representing seven nations, take the other side in Nature.  They call for an international moratorium on HHGE.  This is not a permanent ban, nor is it an international treaty banning HHGE until a subsequent action removed the ban.  Rather, they propose that for a fixed time (they suggest 5 years), nations as a group agree to block, and scientists and clinicians agree to abstain from, any attempt to bring a gene-edited baby to pregnancy or birth.  The scientists writing this week would allow research on human embryos to proceed, as part of a broader effort to define the reliability and safety of the editing—something they say has clearly not yet been established. 

During the moratorium, hard work would need to be done for societies to define what people should be edited.  The scientists suggest that HHGE would rightly be limited, pretty strictly, to “genetic correction,” meaning cases in which a defect of a single gene known to cause, or almost certainly to cause, a serious disease would be corrected.  They would not permit genetic enhancement absent “extensive study” into long term and unintended effects, and even then, they say, “substantial uncertainty would probably remain.”  Genetic enhancement, in their view, would include altering genes that increase the risk of diseases.  They don’t cite examples, but it appears that abnormalities like BRCA1 mutations that increase cancer risk are in view here.  Further, which medical conditions would have no alternative to HHGE must be determined.  In most cases, IVF and preimplantation genetic diagnosis would likely suffice, obviating the need to take the profound additional step of HHGE (whatever one may think of the moral status of the human embryo).  The cases eligible for HHGE, they suggest, would be “exceedingly rare,” limited to essentially unavoidable situations for which a “small minority” of genetic diseases is caused by a genetic abnormality that is frequent in the population.  (It seems like such situations would be rare indeed.)  In such cases, they say, “legitimate needs” of couples seeking to have unaffected, biologically related offspring would need to be weighed against “other issues at stake.”

Most critically—and, hardest to achieve—the scientists envision a broad, intensive effort, that is not limited to or driven by scientists and physicians, and that goes beyond current regulatory regimes to include all aspects of society in an effort to achieve broad consensus—neither simple majority nor unanimity, but a situation in which the clear, large majority opinion exists on when and how HHGE should be countenanced.

Whether these tasks could be pulled off in five short years is something to wonder about, and even allowing planning for HHGE under these constricted circumstances raises questions about how we understand our humanity, whether embryos should be treated as raw materials in development of new treatments, and other matters that go deeper than discussions of medical, scientific, and population risks and benefits.  Were the tasks achieved under a moratorium, the authors envision that individual nations would be sovereignly free to go separate ways, with some allowing HHGE, but perhaps others not.

The editors of Nature, without taking a side about a moratorium per se, call for rules to be set, broad societal conversations to take place, research to be carefully overseen to be sure it is on a “safe and sensible” path and to identify and stop the “rogues,” and journals to refuse to publish work that transgresses limits in place at the time.

With something this big, a “presumption to forebear,” rather than a proactive drive to progress, should be the dominating sentiment.  The details are too complex to address in a few articles, a few short blog posts, a few minutes on cable news, or a few passing conversations wedged into the cracks of busy lives.  We should slow down.  We should ALL call for a moratorium. b

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