After a gene-editing experiment in China last year, an international group of experts pushed back forcefully against the idea that science and the world are ready to edit the genome of human embryos. They suggested a moratorium that would give scientists time to create guidelines and standards for such work. That isn't stopping Russian biologist Denis Rebrikov, who runs an in vitro fertilization clinic and has announced his plans to genetically edit human embryos.
The scientists behind the experiment in China, led by researcher He Jiankui, took aim at a gene called CCR5. It's thought that a mutation in this gene can protect people from HIV if they are exposed to the virus. Rebrikov wants to edit the same gene. While a CCR5 mutation may have a protective effect in some instances, there may also be major drawbacks.
Researchers at the University of California, Berkeley, recently showed that mutations in CCR5 could have unforeseen negative impacts, including shortening lifespan. Rebrikov claims that his methodology will be more beneficial and less risky, although exactly how is unclear. The CRISPR/Cas9 system is supposed to target a specific part of the genome, but that specificity isn't perfect - it can potentially also alter parts of the genome that aren't targeted if the target sequences are very similar.
Related: CRISPR Babies May Face Shortened Lifespan
Rebrikov told Science that his "unique" CRISPR system doesn't have the same risk of off-target effects - although he does not offer details in the interview. He already has made an agreement with a clinic that sees HIV patients to find candidate women that want to get pregnant, but don't respond well to drugs used to lessen the likelihood that they will transmit the virus to their pregnancy.
In Rebrikov's interview with Science, the interviewer pointed out that antiretroviral drugs are effective for most HIV-infected people, and there are around one million people infected with HIV in Russia. Therefore, only around thirty HIV-positive Russian women would qualify for this experiment. Rebrikov admitted that his experiment is a proof-of-concept, and that he would be willing to look at other kinds of genetic mutations that result in deafness, blindness or dwarfism. His aim is to try it enough times to apply it more broadly.
Nature contacted several scientists for comment, including Jennifer Doudna, one of the researchers that created the CRISPR/Cas9 gene editing system that's been used in these experiments.
“The technology is not ready,” said Doudna, a University of California Berkeley molecular biologist. “It is not surprising, but it is very disappointing and unsettling.”
Rebrikov will still have to face several Russian regulatory agencies before he proceeds, which will take time. He told Nature it may be as little as one month or as many as three years.
“It is clear that neither scientific self-regulation nor ‘soft law’ are enough to deter scientists willing to defy the worldwide opposition to pursuing reproductive uses of human genome modification,” said Katie Hasson, the Center for Genetics and Society’s Program Director on Genetic Justice.
“It is well past time to initiate meaningful, broadly inclusive, and unrushed discussions of whether heritable genome editing should be permitted,” Hasson added. “In the meantime, we need stronger protections in place to prevent reckless scientists forging ahead without public engagement on a decision with profound consequences for all of us.”
Learn more about the CRISPR/Cas9 gene editing tool from the video above. The video below discusses ethical concerns about the research done on human embryos in China.
Sources: Science, Nature, Center for Genetics and Society