VATIS UPDATE Article

A team of scientists have edited viable human embryos for the first time in the United States. Details of the feat were sketchy at the time, but the researchers revealed their success in correcting a mutation in the gene MYBPC3 that causes a heart condition. “It’s a pretty big milestone. People have been wringing their hands about the U.S. losing its edge because it was China making progress. But the careful work just took longer to get to fruition,” said George Church, at Harvard University.

MYBPC3 has been known as a cause of hypertrophic cardiomyopathy, or muscle thickening in the heart, for decades. Paula Amato and Shoukhrat Mitalipov of Oregon Health & Science University (OHSU), the United States, along with a large team of collaborators, sought to use CRISPR-Cas9 to introduce a break in the DNA at the mutation site, where a proper sequence could then be introduced. They recruited a dozen healthy egg donors and one sperm donor who carried the MYBPC3 defect.

According to the report, the donor managed his heart condition with an implantable defibrillator and medication. The researchers first tested their technique on induced pluripotent stem cells (iPSCs), finding that about 27% of clones were fixed. They then turned to embryos, none of which were intended for implantation. Dozens were treated with CRISPR, some as already-fertilized zygotes (during S-phase) and others as earlier oocytes (during M phase), into which they simultaneously injected sperm and the CRISPR reagents.