Base Editing Achieves High Efficiency in Human Embryos but Raises Safety Concerns
A new study in Nature demonstrates that base editing can efficiently modify the PCSK9 gene in human embryos without causing the severe DNA damage typical of Cas9 tools. While embryos developed normally to the blastocyst stage, researchers observed rare chromosomal abnormalities and off-target edits, concluding that the technology is not yet safe for clinical reproductive use.