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Base Editing Human Embryos Violates 2025 Moratorium

6/10/2026

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Summary

Story summary

Dieter Egli and his Columbia University team demonstrated base editing in human embryos, correcting PCSK9 and HBG pathogenic variants efficiently in a June 1 bioRxiv preprint.
Nathan Treff reported that the edits avoided aneuploidy but caused off-target changes and mosaic embryos.
David Barrett, CEO of the American Society of Gene and Cell Therapy, called the work “unfortunate” because it violates the May 2025 moratorium banning heritable genome editing for ten years.

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Story summary

Dieter Egli and his Columbia University team demonstrated base editing in human embryos, correcting PCSK9 and HBG pathogenic variants efficiently in a June 1 bioRxiv preprint.
Nathan Treff reported that the edits avoided aneuploidy but caused off-target changes and mosaic embryos.
David Barrett, CEO of the American Society of Gene and Cell Therapy, called the work “unfortunate” because it violates the May 2025 moratorium banning heritable genome editing for ten years.