CLN1 (ceroid lipofuscinosis 1), also known as PPT, INCL or PPT1 (palmitoylprotein thioesterase 1), is a 306 amino acid glycosylated protein that localizesto lysosome and is a member of the palmitoyl-protein thioesterase family.CLN1 functions to remove thioester-linked fatty acyl groups from a variety ofsubstrates, such as as palmitate, from modified cysteine residues in proteinsorpeptides during lysosomal degradation. Defects in the gene encoding CLN1are a causeof infantile neuronal ceroid lipofuscinosis 1 (CLN1 or INCL) andneuronal ceroid lipofuscinosis 4 (CLN4). Neuronal ceroid lipofuscinoses areprogressive neurodegenerative, lysosomal storage diseases characterized byintracellular accumulation of autofluorescent liposomal material, with clinicalsymptoms including seizures, dementia, visual loss and/or cerebral atrophy.