8 | New Scientist | 13 July 2019FIVE Russian couples who are deaf
want to try CRISPR gene-editing
so they can have a child who can
hear, biologist Denis Rebrikov has
told New Scientist. He plans to
apply to Russian authorities for
permission in “a couple of weeks”.
The case for using CRISPR for
this purpose is stronger than it is
for trying to make children HIV-
resistant, as attempted previously,
but the risks still outweigh the
benefits, say other researchers.
“Rebrikov is definitely
determined to do some germline
gene editing, and I think we
should take him very seriously,”
says Gaetan Burgio at the
Australian National University.
“But it’s too early, it’s too risky.”
Both would-be parents in each
couple have a recessive form of
deafness, meaning that all their
children would normally inherit
the same condition. While the vast
majority of genetic diseases can
be prevented by screening IVF
embryos before implantation,
with no need for gene editing, this
isn’t an option for these couples.
Several bioethics reports have
suggested that – if it can be donesafely – editing the genes of babies
might be justified in this situation.
That is why Rebrikov at the
Kulakov National Medical
Research Center for Obstetrics,
Gynecology and Perinatology
in Moscow has sought out these
very unusual couples. “It is clear
and understandable to ordinary
people,” he says. “Each new
baby for this pair would be deaf
without gene mutation editing.”
In November, a biophysicist in
China announced that he had
created the first-ever gene-editedbabies using CRISPR. He Jiankui
tried to induce mutations that
protect against HIV by gene-
editing IVF embryos from couples
in which the man is HIV-positive.
His work has been condemned
for many reasons, but one of the
biggest is that there is no need to
resort to such a risky experimental
procedure to prevent these men
giving their children HIV.
In June, Rebrikov told Nature
he plans to use CRISPR to create
HIV-resistant babies, this time for
couples where the mother is HIV-
positive, but again experts have
pointed out that there is no need
for risky gene editing in this case.
Now Rebrikov has told New
Scientist that he also wants to
prevent children inheriting a
form of deafness caused by
mutations in the GJB2 gene.
In western Siberia, many people
have a missing DNA letter in
position 35 of this gene. People
with two copies of this mutation
never develop the ability to hear.Rebrikov has found five couples
in which both would-be parents
are deaf because of this mutation
and don’t want their children to be
deaf too. So he plans to use CRISPR
to correct it in IVF embryos from
these couples. All the embryos
will have two mutations of the
GJB2 gene, and correcting one will
prevent deafness. “Technically,
it is achievable,” says Burgio.
In November, experts in the
field issued a statement saying
this kind of germline genome
editing could be acceptable if risks
were addressed and certain criteria
are met. Those criteria include “a
compelling medical need” and “an
absence of reasonable alternatives”.The five couples don’t have any
other choice if they want to have
their own biological children who
can hear. But not everyone will
agree that there is a compelling
need, because deafness isn’t a life-
threatening disorder. In fact, some
people who are deaf don’t consider
it to be a disability and want their
children to inherit the condition
in order to preserve deaf culture.
The risks of CRISPR haven’t
been addressed either. There is
no proven way to ensure that
gene-edited children won’t have
unintended mutations, or that
every cell in the children’s bodies
will have the corrected gene.
“The first human trials should
start with embryos or infants
with nothing to lose, with fatal
conditions,” says bioethicist
Julian Savulescu at the University
of Oxford. “You should not be
starting with an embryo that
stands to lead a pretty normal life.”
So why isn’t Rebrikov trying
to prevent more deadly genetic
disorders? It is because people
with such recessive disorders
almost never find themselves in
the same situation. For instance,
people with cystic fibrosis usually
die young and are discouraged
from meeting to avoid swapping
the bacteria that infect their lungs.
Savulescu thinks the first gene-
editing trials should involve
couples whose children could
inherit fatal conditions such as
Tay-Sachs, but who refuse to opt
for screening IVF embryos because
they are opposed to destroying
embryos on religious grounds.
If germline gene editing is
shown to be safe, Savulescu thinks
there would then be a moral
imperative to use it to prevent
conditions such as deafness. ❚“You shouldn’t be
starting with an embryo
that stands to lead a
pretty normal life”
News
Gene editingCOURTE
SY
OFDENISREBRIKOVNext CRISPR babies planned
A controversial effort to edit human embryos in an attempt to avoid
deafness could soon be under way, reports Michael Le PageBURG
ER/PHANIE/
SC
IENCE
PHOTO^ LIBRAR
YBabies have their
hearing tested shortly
after they are bornDenis
Rebrikov’s
plans to edit
embryos
have been
condemned