A daring effort is under
way to create the first children whose DNA has been tailored using gene
editing.
By Antonio Regalado
China has already made genetically altered
humans comes just as the world’s leading experts are jetting into Hong Kong for the Second International Summit on Human
Genome Editing.
Arizona State University
who will attend the Hong Kong summit.
China
Darwin
= = = = = = = = = = update as of December 3, 2018 = = = = = = = = = = = =
By Antonio Regalado
MIT Technology Review – November 25, 2018 -- When Chinese researchers first edited
the genes of a human embryo in a lab dish in 2015, it sparked global outcry and
pleas from scientists not to make a baby using the technology, at least for the
present.
It was the invention of a powerful
gene-editing tool, CRISPR, which is cheap and easy to deploy, that made
the birth of humans genetically modified in an in vitro fertilization (IVF)
center a theoretical possibility.
Now, it appears it may already
be happening.
According to Chinese medical
documents posted online this month, a team at the Southern University of
Science and Technology, in Shenzhen, has been recruiting couples in an effort
to create the first gene-edited babies. They planned to eliminate a gene called
CCR5 in hopes of rendering the offspring resistant to HIV, smallpox, and
cholera.
The clinical trial documents
describe a study in which CRISPR is employed to modify human
embryos before they are transferred into women’s uteruses.
The scientist behind the
effort, He Jiankui, did not reply to a list of questions about whether the
undertaking had produced a live birth. Reached by telephone, he declined to
comment.
However, data submitted as
part of the trial listing shows that genetic tests have been carried out on
fetuses as late as 24 weeks, or six months. It’s not known if those pregnancies
were terminated, carried to term, or are ongoing.
[After this story was published, the
Associated Press reported
that according to He, one couple in the trial gave birth to
twin girls this month, though the agency wasn't able to confirm his
claim independently. He also released a promotional video about his project.]
The birth of the first
genetically tailored humans would be a stunning medical achievement, for both
He and China
“In this ever more
competitive global pursuit of applications for gene editing, we hope to be a
stand-out,” He and his team wrote in an ethics statement they submitted last
year. They predicted their innovation “will surpass” the invention of in vitro
fertilization, whose developer was awarded a Nobel Prize in 2010.
Gene-editing summit
The claim that
The purpose of the international
meeting is to help determine whether humans should begin to genetically
modify themselves, and if so, how. That purpose now appears to have been
preempted by the actions of He, an elite biologist recruited back to China from the US
The technology is ethically charged
because changes to an embryo would be inherited by future generations and could
eventually affect the entire gene pool. “We have never done anything that
will change the genes of the human race, and we have never done anything that
will have effects that will go on through the generations,” David Baltimore, a
biologist and former president of the California Institute of Technology, who
chairs the international summit proceedings, said in a pre-recorded message ahead of the event, which
begins Tuesday, November 27.
It appears the organizers of
the summit were also kept in the dark about He’s plans.
Regret and concern
The genetic editing of a
speck-size human embryo carries significant risks, including the risks of
introducing unwanted mutations or yielding a baby whose body is composed
of some edited and some unedited cells. Data on the Chinese trial site indicate
that one of the fetuses is a “mosaic” of cells that had been edited in
different ways.
A gene-editing scientist,
Fyodor Urnov, associate director of the Altius Institute for Biomedical
Sciences, a nonprofit in Seattle, reviewed the Chinese documents and said that,
while incomplete, they do show that “this effort aims to produce a human” with
altered genes.
Urnov called the undertaking
cause for “regret and concern over the fact that gene editing—a powerful and
useful technique—was put to use in a setting where it was unnecessary.” Indeed,
studies are already under way to edit the same gene in the bodies of adults
with HIV. “It is a hard-to-explain foray into human germ-line genetic
engineering that may overshadow in the mind of the public a decade of progress
in gene editing of adults and children to treat existing disease,” he
says.
Big project
In a scientific presentation in 2017
at Cold Spring Harbor Laboratory, which is posted to YouTube, He described a very large series of
preliminary experiments on mice, monkeys, and more than 300 human embryos. One
risk of CRISPR is that it can introduce accidental or “off target” mutations.
But He claimed he found few or no unwanted changes in the test embryos.
He is also the chairman and founder
of a DNA sequencing company called Direct Genomics. A new
breed of biotech companies could ultimately reap a windfall should the new
methods of conferring health benefits on children be widely employed.
According to the clinical
trial plan, genetic measurements would be carried out on embryos and would
continue during pregnancy to check on the status of the fetuses. During his
2017 presentation, He acknowledged that if the first CRISPR baby were
unhealthy, it could prove a disaster.
“We should do this slow and
cautious, since a single case of failure could kill the whole field,” he said.
A listing describing the study was posted in
November, but other trial documents are dated as early as March of 2017. That
was only a month after the National Academy of Sciences in the US
Currently, using a
genetically engineered embryo to establish a pregnancy would be illegal in much
of Europe and prohibited in the United
States China
Public opinion
In recent weeks, He has
begun an active outreach campaign, speaking to ethics advisors, commissioning
an opinion poll in China
“My sense is that the
groundwork for future self-justification is getting laid,” says Benjamin
Hurlbut, a bioethicist from
The new opinion poll, which was
carried out by Sun Yat-Sen University, found wide support for gene editing
among the sampled 4,700 Chinese, including a group of respondents who were
HIV positive. More than 60% favored legalizing edited children if the objective
was to treat or prevent disease. (Polls by the Pew Research Center have
found similar levels support in the US
He’s choice to edit the gene
called CCR5 could prove controversial as well. People without working copies of
the gene are believed to be immune or highly resistant to infection by HIV. In
order to mimic the same result in embryos, however, He’s team has been using
CRISPR to mutate otherwise normal embryos to damage the CCR5 gene.
The attempt to create
children protected from HIV also falls into an ethical gray zone between
treatment and enhancement. That is because the procedure does not appear to
cure any disease or disorder in the embryo, but instead attempts to create a
health advantage, much as a vaccine protects against chicken pox.
For the HIV study, doctors
and AIDS groups recruited Chinese couples in which the man was HIV positive.
The infection has been a growing problem in China
So far, experts have mostly
agreed that gene editing shouldn’t be used to make “designer babies” whose
physical looks or personality has been changed.
He appeared to anticipate
the concerns his study could provoke. “I support gene editing for the treatment
and prevention of disease,” He posted in November to the social media site
WeChat, “but not for enhancement or improving I.Q., which is not beneficial to
society.”
Still, removing the CCR5
gene to create HIV resistance may not present a particularly strong reason to
alter a baby’s heredity. There are easier, less expensive ways to prevent HIV
infection. Also, editing embryos during an IVF procedure would be costly,
high-tech, and likely to remain inaccessible in many poor regions of the world
where HIV is rampant.
A person who knows He said
his scientific ambitions appear to be in line with prevailing social attitudes
in China
Behind the Chinese trial
also lies some bold thinking about how evolution can be shaped by science.
While the natural mutation that disables CCR5 is relatively common in parts of
Northern Europe, it is not found in
Such thinking could, in the
future, yield people who have only the luckiest genes and never suffer
Alzheimer’s, heart disease, or certain infections.
The
text of an academic website that He maintains shows that he sees the
technology in the same historic, and transformative, terms. “For billions of
years, life progressed according to
It concludes: “By correcting
the disease genes … we human[s] can better live in the fast-changing
environment.”
Note: This story was updated
after publication to include claims by He Jiankui that the trial had
produced live births.= = = = = = = = = = update as of December 3, 2018 = = = = = = = = = = = =
Gene
Scientist Jiankui reported missing: https://www.huffingtonpost.com/entry/he-jiankui-missing-crispr-gene-edited-babies_us_5c0641a0e4b0cd916faf700c
No comments:
Post a Comment