Researchers reported a CRISPR/Cas9‑based strategy that precisely targets and excises pathogenic GGC repeat expansions in the NOTCH2NLC gene implicated in neuronal intranuclear inclusion disease (NIID). The preclinical work demonstrates targeted deletion of repeat expansions and reduction of pathological nuclear inclusions in cellular models, advancing a therapeutic gene‑editing approach for repeat‑expansion neurodegeneration. The study highlights challenges in delivery and off‑target assessment for central‑nervous‑system gene editing but marks a notable mechanistic proof of concept toward therapies for genetically defined neurodegenerative disorders.