This kind of gene editing is
banned in the United States.
A Chinese researcher claims he helped make the
world's first genetically edited babies - twin girls whose DNA he said he
altered with a powerful new tool capable of rewriting the very blueprint of
life. If true, it would be a profound leap of science and
ethics.
A US scientist said he took part in the work in
China, but this kind of gene editing is banned in the
United States because the DNA changes can pass to future generations and it
risks harming other genes. Many mainstream scientists think it's too unsafe to
try, and some denounced the Chinese report as human experimentation.
The researcher, He Jiankui of Shenzhen (above), said he
altered embryos for seven couples during fertility treatments, with one
pregnancy resulting thus far. He said his goal was not to cure or prevent an
inherited disease, but to try to bestow a trait that few people naturally have
- an ability to resist possible future infection with HIV, the Aids virus. He
said the parents involved declined to be identified or interviewed, and he
would not say where they live or where the work was done.
There is no independent confirmation of He's claim,
and it has not been published in a journal, where it would be vetted by other
experts. He revealed it on Monday in Hong Kong to one of the organisers of an
international conference on gene editing that is set to begin on
Tuesday, and earlier in interviews with The Associated Press.
"I feel a strong responsibility that it's not
just to make a first, but also make it an example," He said. "Society
will decide what to do next" in terms of allowing or forbidding such
science. Some scientists were astounded to hear of the claim and strongly
condemned it. It's "unconscionable ... an experiment on human beings that
is not morally or ethically defensible," said Dr. Kiran Musunuru, a
University of Pennsylvania gene editing expert and editor of a genetics
journal.
"This is far too premature," said Dr.
Eric Topol, who heads the Scripps Research Translational Institute in
California. "We're dealing with the operating instructions of a human
being. It's a big deal." However, one famed geneticist, Harvard
University's George Church, defended attempting gene editing for HIV, which he
called "a major and growing public health threat." "I think this
is justifiable," Church said of that goal.
In recent years scientists have discovered a
relatively easy way to edit genes, the strands of DNA that govern the body. The
tool, called CRISPR-cas9, makes it possible to operate on DNA to supply a
needed gene or disable one that's causing problems. It's only recently been
tried in adults to treat deadly diseases, and the changes are confined to that
person. Editing sperm, eggs or embryos is different - the changes can be
inherited. In the US, it's not allowed except for lab research. China outlaws
human cloning but not specifically gene editing.
He Jiankui, who goes by "JK," studied at
Rice and Stanford universities in the US before returning to his homeland
to open a lab at Southern University of Science and Technology of China in
Shenzhen, where he also has two genetics companies. The US scientist who
worked with him on this project after He returned to China was physics and
bioengineering professor Michael Deem, who was his adviser at Rice in Houston.
Deem also holds what he called "a small stake" in - and is on the
scientific advisory boards of - He's two companies.
The Chinese researcher said he practised editing
mice, monkey and human embryos in the lab for several years and has applied for
patents on his methods. He said he chose to try embryo gene editing for HIV
because these infections are a big problem in China. He sought to disable a
gene called CCR5 that forms a protein doorway that allows HIV, the virus that
causes AIDS, to enter a cell.
All of the men in the project had HIV and all of
the women did not, but the gene editing was not aimed at preventing the small
risk of transmission, He said. The fathers had their infections deeply
suppressed by standard HIV medicines and there are simple ways to keep them from
infecting offspring that do not involve altering genes. Instead, the appeal was
to offer couples affected by HIV a chance to have a child that might be
protected from a similar fate.
He recruited couples through a Beijing-based
Aids advocacy group called Baihualin. Its leader, known by the pseudonym
"Bai Hua," said it's not uncommon for people with HIV to lose jobs or
have trouble getting medical care if their infections are revealed.
He describes the work
The gene editing occurred during IVF, or lab dish
fertilization. First, sperm was "washed" to separate it from semen,
the fluid where HIV can lurk. A single sperm was placed into a single egg to
create an embryo. Then the gene editing tool was added.
When the embryos were 3 to 5 days old, a few cells
were removed and checked for editing. Couples could choose whether to use
edited or unedited embryos for pregnancy attempts. In all, 16 of 22 embryos
were edited, and 11 embryos were used in six implant attempts before the twin
pregnancy was achieved, He said.
Tests suggest that one twin had both copies of the
intended gene altered and the other twin had just one altered, with no evidence
of harm to other genes, He said. People with one copy of the gene can still get
HIV, although some very limited research suggests their health might decline
more slowly once they do.
Several scientists reviewed materials that He
provided to the AP and said tests so far are insufficient to say the editing
worked or to rule out harm. They also noted evidence that the editing was
incomplete and that at least one twin appears to be a patchwork of cells with
various changes. "It's almost like not editing at all" if only some
of certain cells were altered, because HIV infection can still occur, Church
said.
Church and Musunuru questioned the decision to
allow one of the embryos to be used in a pregnancy attempt, because the Chinese
researchers said they knew in advance that both copies of the intended gene had
not been altered. "In that child, there really was almost nothing to be gained
in terms of protection against HIV and yet you're exposing that child to all
the unknown safety risks," Musunuru said.
The use of that embryo suggests that the
researchers' "main emphasis was on testing editing rather than avoiding
this disease," Church said. Even if editing worked perfectly, people
without normal CCR5 genes face higher risks of getting certain other viruses,
such as West Nile, and of dying from the flu. Since there are many ways to
prevent HIV infection and it's very treatable if it occurs, those other medical
risks are a concern, Musunuru said.
There also are questions about the way He said he
proceeded. He gave official notice of his work long after he said he started it
- on November 8, on a Chinese registry of clinical trials. It's unclear whether
participants fully understood the purpose and potential risks and benefits. For
example, consent forms called the project an "AIDS vaccine
development" programme.
The Rice scientist, Deem, said he was present in
China when potential participants gave their consent and that he
"absolutely" thinks they were able to understand the risks. Deem said
he worked with He on vaccine research at Rice and considers the gene editing
similar to a vaccine. "That might be a layman's way of describing
it," he said. Both men are physics experts with no experience running
human clinical trials.
The Chinese scientist, He, said he personally made
the goals clear and told participants that embryo gene editing has never been
tried before and carries risks. He said he also would provide insurance
coverage for any children conceived through the project and plans medical
follow up until the children are 18 and longer if they agree once they're
adults.
Further pregnancy attempts are on hold until the
safety of this one is analysed and experts in the field weigh in, but
participants were not told in advance that they might not have a chance to try
what they signed up for once a "first" was achieved, He acknowledged.
Free fertility treatment was part of the deal they were offered.
He sought and received approval for his project
from Shenzhen Harmonicare Women's and Children's Hospital, which is not one of
the four hospitals that He said provided embryos for his research or the
pregnancy attempts. Some staff at some of the other hospitals were kept in the
dark about the nature of the research, which He and Deem said was done to keep
some participants' HIV infection from being disclosed.
"We think this is ethical," said Lin
Zhitong, a Harmonicare administrator who heads the ethics panel. Any medical
staff who handled samples that might contain HIV were aware, He said. An
embryologist in He's lab, Qin Jinzhou, confirmed to the AP that he did sperm
washing and injected the gene editing tool in some of the pregnancy attempts.
The study participants are not ethicists, He said,
but "are as much authorities on what is correct and what is wrong because
it's their life on the line." "I believe this is going to help the
families and their children," He said. If it causes unwanted side effects
or harm, "I would feel the same pain as they do and it's going to be my
own responsibility."
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