The neuronal ceroid-lipofuscinoses (Batten disease): A new class of lysosomal storage diseases

The neuronal ceroid-lipofuscinoses (Batten disease) are a group of severe n eurodegenerative disorders characterized clinically by visual loss, seizure s and psychomotor degeneration, and pathologically by loss of neurons and l ysosomal accumulation of autofluorescent storage material resembling ageing pigment. To date, eight genetic loci have been identified (CLN1-8). Four C LN genes have been isolated (CLN1, CLN2, CLN3 and CLN5) and their gene prod ucts have been characterized. CLN1 is a lysosomal palmitoyl-protein thioest erase (PPT) and CLN2 is a lysosomal pepstatin-insensitive peptidase. CLN3 a nd CLN5 are proteins with multiple membrane-spanning regions and have no ho mologies to other proteins that would suggest their function. The CLN3 prot ein is associated with lysosomal membranes and the intracellular location o f the CLN5 protein is unknown. Therefore, there is ample evidence that the neuronal ceroid-lipofuscinoses represent a new class of lysosomal storage d isorders.