CRISPR/Cas9-mediated gene editing in human tripronuclear zygotes

This 2015 study describes an experiment that utilized CRISPR/Cas9 to modify human embryos in vitro. These embryos were pre-implantation and nonviable, and the study identified technical difficulties with embryonic CRISPR modification, including poor DNA repair and off-target effects. Nonetheless, the publication of this research prompted the US National Academies of Sciences and Medicine to organize the first International Summit on Human Gene Editing later that same year.