JANUARY/FEBRUARY 2020. DISCOVER 33i
Often, science moves ahead incrementally. Yet
sometimes it advances in dramatic leaps and
bounds that can stir new hopes for medical benefits
while shaking society to its very core. We saw both
in 2019, as work using the gene-editing tool CRISPR
gained momentum.
The year opened with the scientific community scrambling
to respond to the news that Chinese researcher He Jiankui
had used CRISPR technology to edit the genomes of human
embryos. The experiments resulted in the November 2018 birth
of twin girls, the first humans with genetically altered germline
cells — which means their genetic changes are heritable and can
be passed on to future generations.
The National Institutes of Health (NIH), a crucial public sup-
porter of biomedical research, is among the many who consider
such experiments both irresponsible and unethical. The NIH
has not funded any use of heritable gene-editing technologies
in human embryos, and it has no intention of doing so.
But NIH’s strong stance against heritable gene editing does
not mean that we think CRISPR has no role in the future of clin-
ical medicine. This innovative technology possesses enormous
potential for therapeutic good if used for making nonheritable
genetic changes. In that approach, genetic material is altered
only in relevant somatic (nonreproductive) cells, so there is no
chance of passing those changes on to future offspring.
NIH’s highest priorities in 2019 included supporting research
aimed at using nonheritable gene editing to help people with life-
threatening disorders, such as sickle cell disease, HIV infection,
cancer and muscular dystrophy. Indeed, such applications may
offer the best hope not only for treating, but for curing, many of
the nearly 6,000 human genetic diseases that still lack treatments.
Now, scientists and leaders around the globe have an obliga-
tion to consider the appropriate use — if any — of heritable
human gene editing. This involves scrutinizing the safety of
such experiments, including the risk of unintended mutations,
as well as a clear-eyed analysis of actual medical need. In our
view, the current arguments — that the benefits outweigh the
risks — are surprisingly uncompelling. But our deliberations
should not stop there. We must weigh the profound social,
ethical and moral issues associated with modifying the germline
in ways that could change the human species forever.Given the significance of these decisions, in March, lead-
ing scientists from seven countries — led by Eric Lander and
including CRISPR pioneers Feng Zhang and Emmanuelle
Charpentier — called for a five-year international moratorium
on the use of gene editing to modify the human germline for
clinical purposes. The NIH supports such a moratorium.
Despite the calls for caution, some researchers are forging
ahead. In June, Russian molecular biologist Denis Rebrikov
announced plans to implant gene-edited embryos into women.
Like his Chinese counterpart, Rebrikov planned to use CRISPR
to target the CCR5 gene to protect against HIV; he later changed
course to focus on GJB2, a gene linked to heritable hearing loss.
Direct editing of embryos is not the only way to alter the
human germline in heritable ways: In August, New York-based
reproductive biologist Gianpiero Palermo went public with his
plans to use CRISPR technology to target a gene that increases
cancer risk in human sperm.
But such moves continued to meet vigorous opposition. In
August, a number of research groups working on gene-editing
therapeutics issued a statement asserting heritable gene editing
is currently inappropriate for use in human clinical studies.
That same month, a group of international research societies
convened to discuss recommendations for appropriate research,
which are slated for completion in spring of 2020.
Meanwhile, the World Health Organization’s new expert
advisory committee, convened in the wake of He’s experiments,
sidestepped the issue of a moratorium at its August meeting.
It did, however, establish a global registry to track all kinds
of human gene-editing research and to offer consultation on
governance of such technologies.
A moratorium of at least five years on heritable human gene
editing would provide us time to engage in proactive, rather than
reactive, discussions about the future of such technology. That
discussion has to be inclusive of many societal perspectives.
We must never allow our technology to eclipse our humanity.
As an interconnected global society, we have a responsibility
to ask ourselves some very hard questions about heritable gene
editing and the dangers of human hubris. While difficult, this
is a debate that we simply cannot afford to postpone.Francis S. Collins is the director of the National Institutes of Health.The First Gene-Edited
Babies Turn 1
BY FRANCIS S. COLLINSESSAY
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