Urine‐Derived iPSC Neurospheres Uncover Proteomic Correlates of Clinical Severity in Dravet Syndrome

Dravet syndrome (DS) is a rare and severe childhood-onset developmental epileptic encephalopathy caused primarily by mutations in the sodium channel gene SCN1A. Animal models have undeniably advanced our understanding of DS, but they still do not fully capture its clinical heterogeneity, highlighting the need for complementary human in vitro systems. Here, we generated induced pluripotent stem cells (iPSCs) from urine epithelial cells of three DS patients carrying distinct SCN1A variants and differentiated them into neural stem cells (NSCs) and early-stage neurospheres. Clinical severity was assessed using the DANCE checklist, and molecular phenotypes were characterized through isobaric quantitative proteomics. Comparative analyses identified differences in protein abundance across patient-derived lines, with distinct molecular patterns associated with clinical severity measures. The patient-derived lines exhibited variability in protein groups related to synaptic organization, mitochondrial processes, and RNA processing, reflecting interindividual molecular differences within the cohort. These findings establish patient-derived neurospheres as a scalable human model for investigating molecular variability in DS. This approach provides a framework to explore disease heterogeneity and provides a foundation for future studies linking molecular profiles to clinical variability in DS.