Scientists at the Broad Institute and The Jackson Laboratory have used prime editing—a next-generation CRISPR technique sometimes dubbed “CRISPR 3.0”—to repair five disease-causing mutations in the ATP1A3 gene that underlie most cases of alternating hemiplegia of childhood (AHC), a severe neurodevelopmental disorder with no approved therapy. In two mouse models, researchers delivered adeno-associated viruses carrying the prime-editing machinery directly into the brain shortly after birth. The intervention corrected 48 % of genomic lesions and 73 % of mutant transcripts in the cerebral cortex, restored ATP1A3 protein function, cut seizure-like episodes and motor deficits, and more than doubled median survival compared with untreated animals. In parallel, up to 90 % of mutant alleles were corrected in patient-derived cells in vitro. The work, published 21 July 2025 in Cell, is the first demonstration that prime editing can durably ameliorate a neurological disease in vivo. The programme—developed with financial and strategic input from the patient-advocacy group RARE Hope—provides a framework for tackling multiple mutations simultaneously, potentially accelerating therapy development for other rare brain disorders. The team is now evaluating systemic and later-life delivery options to ease translation to the clinic. While human trials are not imminent, the results strengthen prime editing’s candidacy as a versatile tool for precision gene repair inside the central nervous system.