Play Live Radio
Next Up:
0:00
0:00
Available On Air Stations
KPBS Midday Edition

Salk Scientists Contribute To First Gene Editing Of Human Embryos In US

Salk scientists Juan Carlos Izpisua Belmonte and Jun Wu are seen in this undated photo.
Salk Institute
Salk scientists Juan Carlos Izpisua Belmonte and Jun Wu are seen in this undated photo.
Salk Scientists Contribute To First Gene Editing Of Human Embryos In US
Salk Scientists Contribute To First Gene Editing Of Human Embryos In US GUEST: David Wagner, science reporter, KPBS

Scientists at the Salk Institute are part of a team reporting a breakthrough in human gene editing. The researchers were able to correct a mutation in the early stage areas linked to an inherited heart disease. A rare heart ailments sometimes causes sun death in otherwise healthy young people. This is the first time researchers have announced success in editing embryonic DNA. Chinese scientists made the first attempts to years ago. The vision of being able to correct genetic mutations is the promise of this research. Some say the threat is the potential for hand-picked genes for designer babies. Joining me is David Wagner, science -- science reporter. Welcome. The discovery is based on a technology some people may have heard about. Crisper. What can I do ?This is a technique that was discovered recently and it is described as a pair of binoculars scissors. Science can precisely target a specific gene to cut it and replace that gene with any kind of desired DNA that they can build into a template. It is not a perfect approach but you can think of it as a cut and paste program for DNA. Because it is easy to use, scientists have been using it to modify plans, insects, animals and now human embryos.Crisper was used on human embryos in China two years ago. What was the innovation here ?In 2015, Chinese scientists tried to use crisper on nine viable embryos, those that had no chance of turning into a fetus. They found that the edits were imprecise. Crisper did not get all of the embryos to take out the edits or when they did come other edits were made two different genes that they did not intend on making where they ended up with embryos that had cells some containing the edits and some that did not. Basically, the conclusion was, crisper might not really work in human embryos if your goal is to target a specific gene. Now comes this paper. They show you can specifically target a diseased causing mutation and corrected in human embryos without the unintended errors.What disease were the scientists trying to prevent ?It is the heart disease that is and headed -- inherited. It is a serious mutation. If you had one bad copy, it can lead to heart failure and sudden death. One out of 500 people have it. It is a leading cause of death in healthy young athletes. The scientists who led the research says he wants to move forward with clinical trials to see if this approach could create children that are free of a genetic disease. I talked to Salk scientists who is one of the people involved and he said a lot more needs to be done before we start trying to create children with this approach. Let's hear his take. Back at this stage it this is research and we need more research like this before we can consider going forward.The ethics of experimenting on human embryos remains controversial. Isn't that cold germline editing ?If a baby were brought to term using this approach, it would result in germline editing. To be clear, they never intended to implant the ambience or bring them to turn. There was no intention of creating a baby. What is that? It is this idea that you would make a change to an embryo that would not only affect that person but because you would then be altering their sperm or egg cells, that would be passed down to their children and their decisions. This is controversial because are we in a position to make such a big decision about not just one person but the descendents? Do we know that is safe? Even if there is a strong argument to do this to prevent deadly diseases, what if we are talking about taking other kinds of changes to nonmedical traits that are inherited for many generations? That is the controversy. That is why so far we have only seen the studies done in China where the ethical and cultural dimensions of this are different than they are in the U.S. It is notable that this study is that U.S. is coming out after a big report came out from the national Academy of science on human genome editing that urges caution but keeps the door opens -- opened and says in some cases, this could be appropriate experimentation.There is a federal ban on funding clinical trials on this work. Where did the money come from for this research ?That is right. Federal agencies will not this work and the FDA will not consider clinical trials using this method. The money came from private foundations and from university resources. It is not illegal in the US to carry out a study like this but it is not something that talks -- tax dollars will fund.This gets people talking about the possibility of parents choosing gene to make designer baiters -- babies. What do the researchers say ?That is the question that comes up with a study like this. In the future if parents are rich enough to afford a theoretical residual like this will they get to look at a menu of desirable traits and pick and choose what they want? Like intelligence and height and athletic ability XI asked the researchers but I asked bioethicist about their take. They said no. Based on what we see in the study and what they have done so far, this is not the done Don of the designer baby era. First, the experiments were not successful at inserting a lab grown gene into the embryos. They relied on the maternal good copy of the gene to ensure the embryos avoided having the disease copy of that mutation but they were not able to stick a lab guarantee into the embryos. That suggests that even if you could create a gene for high IQ, this is not possible but let's say you could. This experiment suggests that we are not at the stage where you can insert that into a human embryo. I put this question to Salk scientists and the scientists do not know what gene or genes are correlated with things like IQ or athletic ability. Let's hear what he said.We should not apply this technology in any shape or form towards designer babies. The reason for that is we do not know the technology. The technology is not there. Even if it is, there are other considerations and ethical considerations and also scientific imitations.The bottom line, this study is a real step toward demonstrating that you could Jean edit human embryo to correct certain disease causing genes in a limited case but we are not about to enter this Gattaca future.I've been speaking with David Wagner. Thank you.Thank you.

Salk Scientists Contribute To First Gene Editing Of Human Embryos In US
Salk scientists were involved in a new study that raises the possibility of curing certain genetic diseases in future generations. But the prospect of editing a child's DNA before they are born remains very controversial.

Scientists at the Salk Institute in La Jolla have helped to edit the DNA of human embryos for the first time in the United States.

They contributed to a study published Wednesday in the journal Nature showing that a mutation linked with a deadly, inherited heart disease can be successfully corrected in early-stage embryos using the gene editing tool CRISPR.

The researchers, led by Shoukhrat Mitalipov at the Oregon Health & Science University, say their results suggest CRIPSR could be a powerful technique for correcting disease-causing genetic mutations in developing human embryos.

But in an interview with KPBS, a Salk scientist involved in the study said more scientific work and ethical consideration is needed before using this approach in the creation of any future human children.

"We need much more basic studies like this to answer the question of whether this is a feasible approach," said Salk staff scientist Jun Wu, who contributed to the study along with Salk researchers Juan Carlos Izpisua Belmonte and Keiichiro Suzuki.

"At this stage, I would say this is still basic research," Wu said. "And we need more basic research like this before we can even consider going forward."

The scientists targeted a mutation in the gene MYBPC3. Having one bad copy of this gene can lead to heart failure and sudden death. The disease affects 1 in 500 people, and is a leading cause of death in otherwise healthy athletes. A patient with this mutation donated his sperm and skin cells for the study.

The scientists in Oregon obtained the eggs for the research and brought their expertise in embryo biology to the study. The Salk scientists contributed by developing the gene editing strategy, initially testing it in stem cells derived from the patient's skin cells.

In 2015, scientists in China conducted the first known attempt to use CRISPR on human embryos. But they found that their edits were imprecise.

Those results raised concerns that any effort to manipulate genes in a human embryo could lead to unintended edits in other genes — known as "off-target effects" — or could lead to embryos containing a mixture of cells with corrected genes and cells with uncorrected genes, a problem known as "mosaicism" that could end up failing to prevent disease.

Wu and his colleagues were able to avoid these problems in their experiments, leading other scientists to describe their results as a "step forward" in comparison to previous studies.

"The very low level of off-target effects (actually apparently not distinguishable from background genomic variation) is very encouraging for future applications," said MIT scientist Richard Hynes, who co-chaired a National Academy of Sciences report on human genome editing released earlier this year.

"Their method is not yet proven to work for other genes and is not yet 100 percent efficient," Hynes wrote in an email to KPBS. "So more work would be needed before this could potentially be used for heritable germline editing."

Wu said timing was key for preventing off-target effects and mosaicism. The scientists made the gene edits early in the embryos' development and saw the efficiency of DNA correction go up.

"We delivered the editing tools earlier. At the one-cell stage, the embryo has enough time to make the repair before they make copies of the DNA," Wu said.

Scientists contacted by KPBS saw these results as a small yet successful step toward the development of new strategies for fighting genetic diseases in future generations. But the prospect of editing a child's DNA before they are born remains very controversial.

Because these edits would not only affect that child, but could also be passed down to their descendants, some ethicists are firmly opposed to editing of the human "germline." In a 2015 statement regarding its policy against funding research on gene-editing in human embryos, the National Institutes of Health said germline editing "has been viewed almost universally as a line that should not be crossed."

The Salk scientists and their colleagues say they never intended to implant any of the embryos used in their research, much less to bring any of those embryos to term. Their work was largely funded by private donations and university money.

Other strategies currently exist for preventing genetic diseases in offspring. Embryos can be genetically screened before they are implanted during in vitro fertilization.

But the scientists note that in certain rare cases, existing strategies are not enough to help parents conceive a child free of a genetic disease. They say it remains to be seen in future studies whether this approach will be successful at correcting other mutations.

"One thing clear at this stage is that we shouldn't apply this technology in any shape or form toward designer babies," Wu said. "The technology is not there yet. And even if it was there, there is still a lot of ethical considerations and scientific limitations. For many of the traits that people want in their next generation, there's not a single underlying gene."

Ethicists told KPBS the researchers have not raised any new problems that were not already known prior to the study's publication.

"This is not the dawn of the era of the designer baby," said University of Wisconsin bioethicist and law professor Alta Charo in an email. "The need for embryo editing to avoid passing a serious disorder to one's children is limited to a small number of situations. In addition, we are already in clinical trials for use of editing to treat diseases in those already born."

Michael Kalichman, director of the Research Ethics Program at UC San Diego, agreed that the study did not signal that parents will soon have the option to pick and choose from a menu of desired traits for their offspring.

"Although it implies a future in which we could choose to have children without particular genetic diseases, or even design for particular traits, that is still likely a very long time from now," he wrote in an email to KPBS.

"On the other hand, the trajectory is for this technology to be sufficiently robust that it will eventually be used," Kalichman wrote. "In anticipation of that use, it is essential that the general public, not just the scientists and clinicians, needs to learn about and consider the implications of the potential applications."

This is not the first time Wu and his Salk colleagues have been involved in research that, even if it has not crossed ethical lines, has raised ethical questions. Earlier this year, they reported creating partially human pig embryos as a way to explore the idea of growing humanized organs in animals in order to address shortages of transplantable organs.