[Pitfalls in the clinical and electroencephalographic diagnosis of ceroid lipofuscinosis].

Neuronal ceroid lipofuscinosis (NCL) were traditionally classified according to age of onset and clinical features in four main groups. Recently, a combination of clinical, ultra structural and genetics data led to the recognition of eight forms of NCL, providing a more precise framework to classify atypical cases. By the other hand, it was shown that mutations in the same gene could be responsible for a large variety of clinical phenotypes. The objective of this study is to describe two brothers with clinical and electroencephalographic abnormalities characteristic of juvenile NCL, but with ultra structural abnormalities suggestive of late infantile NCL. Electroencephalogram is useful for clinical diagnosis of NCL but it is not helpful in its classification.