LOW-MOLECULAR-WEIGHT STORAGE MATERIAL IN INFANTILE CEROID-LIPOFUSCINOSIS (CLN1)

The identification of the genetic defect in CLN1 as a palmitoyl-protei n thioesterase deficiency initiated a search for the lysosomal storage material. Pulse-chase labelling of fibroblasts and lymphoblastoid cel l lines with [S-35]cysteine revealed the presence of lipid [S-35]cyste ine material in CLN1 fibroblasts and not in controls, CLN2 or CLN3 pat ients or other patients with lipidosis. A single band comigrated with the acylcysteine standard and labelling with [H-3]palmitate showed a b and of material which eluted from the silicic acid column with the pho spholipid fraction and which co-migrated with the lipid-[S-35]cysteine band. The storage material is tentatively identified as palmitoylcyst eine.