Clinicopathological studies of a series of nine children with a new subform of Jansky-Bielschowsky disease or late infantile neuronal ceroid lipofuscinosis (LINCL) is presented. The onset of this subform is between 2.5-3.5 years of age with initial neurological symptoms of abnormal motor skills caused by cerebellar and extrapyramidal signs. Soon after dementia, myoclonic seizures are followed. Visual impairment is more clearly seen after the age of 5 or 6 years. The ultrastructural studies of the skin and/or buffy coat showed abundant lysosomal storage of curvilinear profiles, rarely intermixed with fingerprint profiles. The MRI of the head performed in seven cases, showed initially enlargement of the ventricles that is secondary to basal ganglia atrophy and presence of cerebellar and cerebral atrophy. In 4 of 7 cases (Cases 1, 5, 6, 8) abnormalities in the deep white matter showing increased signals of T2-weighted imaging in the periventricular areas of the fronto-parietal region, internal capsule, tracks of the brainstem, and white matter of cerebellum were seen. These abnormalities were also observed by post-mortem neuropathological studies in three cases (nos. 7-9). The MRI in Cases 7 and 9 was not performed. The electrophysiological abnormalities (EEG, ERG, VER) are similar as described in the classical LINCL. Neuropathological studies done in 3 of 9 cases showed generalized brain atrophy and unique type of neuronal cytoplasmic inclusion body in the basal ganglia, brainstem, dentate nuclei, and rarely, cerebral cortex. These large, round neuronal cytoplasmic inclusions were pink in hematoxylin (HE), violet in cresyl violet, and dark blue with Kluver-Barrera method.(ABSTRACT TRUNCATED AT 250 WORDS)

Department of Pathology Prague Medical School Czech Republic

New York State Office of Mental Retardation and Developmental Disabilities Department of Pathological Neurobiology Staten Island 10314