Nature study shows that its possible to safely repair fatal defects in embryos, paving the way for the potential use of CRISPR in the clinic.  

Sometimes it feels like the field of gene editing is traveling at warp speed. Five years ago the invention of CRISPR-Cas9 become a mainstay of biological research. Eighteen months ago, Chinese scientists applied CRISPR to human embryos. Now, in a study reported today in Nature, a team of international scientists led by Oregon Health and Science University took another giant step forward and successfully edited genes in human embryos to repair a common and serious disease-causing mutation.

The effort corrected a pathogenic mutation in fertilized embryos that causes hypertrophic cardiomyopathy, a muscle thickening that leads to heart failure. The MYBPC3 mutation is found at frequencies ranging from 2% to 8% in major Indian populations. To carry out the experiment, a sperm donor carrying the MYBPC3 defect was recruited along with 10 healthy egg donors to create the embryos. To reduce the chance of off-target mutations—a major safety concern with CRISPR—the  scientists injected the CRISPR material alongside the sperm.

None of the fertilized genes were implanted in women, but the findings do open the door to the possibility that gene editing may one day be used to prevent a variety of inherited defects in babies. “Targeted gene correction can potentially rescue a substantial portion of mutant human embryos, thus increasing the number of embryos available for transfer,” the authors of the study said.

The New York Times noted that the study came a few months after a national scientific committee recommended new guidelines for modifying embryos, easing blanket proscriptions but urging it be used only for dire medical problems. And in a commentary accompanying the study in Nature, scientists Nerges Winblad and Frederik Lanner at the Karlinska Institute in Sweden said more research is needed to confirm that the approach is safe on a number of different levels before it can be used as a therapy for inherited diseases. “Nevertheless, this study is paving the way as part of investigations that might lead to CRISPR–Cas9 reaching the clinic in the future. Until then, embryo genetic testing during IVF remains the standard way to prevent the transmission of inherited diseases in human embryos,” they wrote.

Check out The Scientist, The Washington Post, Xconomy and The Atlantic for other coverage of this story.

And if you are interested in reading more about CRISPR in animal model creation, check out Eureka’s recent video blog, Cut and Paste.