Paediatric‐onset neuronal ceroid lipofuscinosis: first symptoms and presentation at diagnosis

Neuronal ceroid lipofuscinoses (NCLs) are rare, progressive disorders. Through this series of 20 patients with NCL, we illustrate differences between subtypes in their presenting symptoms and clinical, imaging, and electrophysiological results to raise awareness of symptom diversity. Data were available on presenting symptoms, genetics, magnetic resonance imaging (MRI), electroencephalography (including with low‐frequency intermittent photic stimulation), visual responses, and electron microscopy. Causal mutations were identified in 10 patients. Eleven patients had neuronal ceroid lipofuscinosis type 2 (CLN2) disease and their most common presenting symptom was seizures, although motor and language defects were also reported. Five patients with CLN2 disease showed abnormalities at initial MRI, but only three showed a photic response with low‐frequency stimulation. Seizures were not as common a presenting symptom in other NCL subtypes. Patients with NCLs present with diverse symptoms, which may not be characteristic in early disease stages. These signs and symptoms should lead to rapid diagnostic confirmatory testing for NCLs.