RESUMEN
Neuronal ceroid lipofuscinoses (NCL) are the most common childhood neurodegenerative disorders. Clinical features include seizures, blindness, psychomotor deterioration, the age of onset differ for each NCL type. Diagnosis of late infantile NCL relies on the characteristic clinical presentation, electrophysiological and neuroradiological findings, and identification of the ultrastructural abnormalities. The Photoparoxsmal response provide diagnostic clues to an atypical case of Infantile NCL in which results of extraneuronal biopsies were negative and MRI findings resembles leukodystrophy. Photic stimulation with 2 to 5 Hz activity elicited discrete spike and wave discharges in the occipital region on electroencephalogram and no sleep spindles are present. In patients with rapid neurologic deterioration, diagnosis of NCL should be considered and an EEG must be performed using photic stimulation to look for characteristic findings.