Presynaptic impairment in Niemann-Pick C1-deficient neurons: Not dependent on presence of glial cells

► Both glutamatergic and GABAergic NPC1−/− synapses show presynaptic defects. ► Postsynaptic properties were normal in NPC1−/− neurons. ► NPC1−/− neurons exhibit presynaptic vesicle exocytosis deficiency. ► Synaptic vesicle exocytosis defects in NPC1−/− neurons is not dependent on glia.