Photosensitivity is an early marker of neuronal ceroid lipofuscinosis type 2 disease

Abstract

Early photosensitivity (typically PPR at low stimulation frequencies of 1-3 Hz) is a hallmark of CLN2 disease. This diagnosis should be considered in a child presenting with any type of seizure, and particularly if it is accompanied by delayed speech and/or ataxia or MRI abnormalities (posterior white matter signal alteration or cerebellar atrophy).