Neuronal intranuclear inclusion disease (NIID) is a rare autosomal dominant neurodegenerative disorder defined by the presence of eosinophilic intranuclear inclusions across both central and peripheral components of the nervous system, as well as multiple visceral organs, resulting in pronounced clinical heterogeneity. Following the discovery of pathogenic GGC repeat expansions in the <i>NOTCH2NLC</i> gene as the underlying genetic driver, a diverse array of experimental platforms has been established to probe NII…