Dangers of CRISPR

MARY REICHARD, HOST: Coming up next on The World and Everything in It: the unintended consequences of editing human genes.

NICK EICHER, HOST: CRISPR is an intricate gene-editing technology. It can remove bad genes or insert good ones. It has the potential to cure diseases like cancer or muscular dystrophy.

REICHARD: But it’s not without controversy. Ethicists fear this type of gene-editing could lead to things like “designer babies” or inadvertently pass genetic problems to future generations. Now researchers have discovered a new problem: accidental genetic changes.

WORLD Radio’s Kristen Flavin has the details.

KRISTEN FLAVIN, REPORTER: CRISPR cuts DNA at specific points to either delete or insert genetic material. Researchers at the University of California, Berkeley in 2012 found a way to use CRISPR to cure and prevent a wide variety of diseases.

NPR’s podcast RadioLab explained CRISPR as little surgeons on a search and destroy mission targeting bad genes.

AUDIO: Say you’ve got a mouse with something like hemophilia. This is a disease that’s caused by one bad gene. So what you do is you take these little surgeons, you give them the mugshot for the bad gene. Then you stick the surgeon with the new mugshot in a mouse. Then you set it loose. And, just like it’s programmed to, it will find that gene and —click, click, chop. The scissors will end up cutting exactly the gene you wanted to cut.

But researchers at the Wellcome Sanger Institute in England recently discovered CRISPR may cause a great deal of unintended genetic damage. They published their findings in the scientific journal Nature Methods.

The CRISPR technique can have negative consequences if it accidentally modifies part of the DNA researchers didn’t intend to target. Until now, researchers only looked for unintended alterations in the immediate area of CRISPR editing.

David Prentice is the vice president and research director for the Charlotte Lozier Institute in Washington.

PRENTICE: The idea would be that you cut, let’s say a faulty gene, a mutated gene out and the cell will put in the bonafide non-mutated copy. CRISPR’s utility is going to be its specificity in terms of making any sort of genetic engineering or gene editing changes. But the problem is it’s not 100 percent specific or accurate, which can potentially lead to some significant problems in what’s called off target cutting.

The researchers in this new study looked at an area within the targeted gene, but not close to the specific point of editing—that’s where CRISPR frequently caused extensive mutations. Those mutations could lead to switching important genes on or off and could cause dangerous changes in many cells.

PRENTICE: You want it just to cut at the target, at the very specific piece of DNA that you want to alter. But if it’s making cuts other places around the genome, you could introduce mutations instead of remove mutations. And this could be very significant in terms of health, even life threatening.

According to the researchers, the gene damage they found represented a common outcome of CRISPR. They say scientists previously underestimated the DNA changes.

Some experts are not alarmed, calling the study’s findings an extraordinary overstatement. And some biotech companies hoping to commercialize CRISPR also downplayed the study.

Derek Dykzhoorn is an associate professor at the University of Miami Miller School of Medicine. He believes the study’s findings will help improve the technology.

DYKZHOORN: I think it’s important for us to know all of the ways in which these technologies work and some of the downsides of them, so we can actually build better tools. So, from the sense of overstating it, I think we need to understand it in the context of the experiment that they did and the specific thing they were looking for. 

Gary Beecham is an associate professor in the Hussman Institute for Human Genetics—also at the University of Miami. He agrees with Dykzhoorn.

BEECHAM: CRISPR is a tool and, like any tool, it can be used for good or it can be used for bad. And the positive is that, yes, you can use it to potentially treat or cure diseases. So, the upside is tremendous. There are ethical concerns, though. First and foremost, like any treatment, is it safe?

Ultimately, Beecham says the scientists developing CRISPR to fight disease are doing their part to mitigate the consequences of sin but must remain alert to the dangers.

BEECHAM: All biomedical science in terms of alleviating suffering and illness, fits squarely within a Christian ethic of fighting against sin. Now as Christians, the critical thing is that Christ won that battle at the cross. But we’re still living it out in different ways. I think we shouldn’t necessarily be afraid of the new scientific techniques, but there are still ethical considerations to think of.

Reporting for WORLD Radio, I’m Kristen Flavin.

(Photo/iStock.com/manop1984)

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