Abstract Progressive myoclonic epilepsy (PME) in childhood suggests an underlying neurodegenerative disorder, particularly when associated with organomegaly and gaze palsy. Niemann–Pick disease type C (NPC) is a rare lysosomal storage disorder that may present with PME, often with nonspecific neuroimaging findings. An 11-year-old boy presented with progressive cognitive decline, multifocal myoclonus, generalized seizures, hepatosplenomegaly, and vertical supranuclear gaze palsy. Magnetic resonance imaging showed mild diffuse cortical atrophy. Bone marrow examination revealed foamy storage histiocytes, and exome sequencing identified compound heterozygous pathogenic variants in the NPC2 gene, confirming NPC type C2. This case emphasizes the importance of clinical recognition and genetic confirmation of NPC in children with PME and systemic involvement, even when neuroimaging findings are nonspecific.
Singh et al. (Mon,) studied this question.