In utero base editing corrects metabolic birth defect

Researchers from Children's Hospital of Philadelphia and University of Pennsylvania opened the door to prenatal genome editing by using a relatively new CRISPR-based approach called base editor 3 to correct tyrosinemia type I, a rare metabolic birth defect, in utero in mice.

In a paper published Monday in Nature Medicine, the researchers developed a viral vector system for in utero delivery of base editor 3, a protein-RNA complex adapted from the CRISPR-Cas9 (CRISPR-associated protein 9) system that combines a catalytically inactive version of Cas9 with cytidine deaminase to edit specific bases without cutting DNA. Base editing is thought to be a safer alternative to CRISPR-Cas9 because it does not edit using double-stranded breaks that can lead to off-target effects of homology-directed repair...