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Posted on March 14, 2019 at 9:59 PM
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.


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