The majority of lysosomal storage diseases affect the central nervous system. Those that reflect a primary lysosomal disorder are associated with genetically determined deficiencies of specific lysosomal enzymes and storage of the relevant substrate. Autofluorescent lipopigments accumulate in the ceroid-lipofuscinoses, a heterogeneous group of diseases in which lysosomal storage is thought to be a secondary event. In animals, there occurs a group of toxic storage diseases whose pathology mimics that of some of the genetic diseases. In humans some element of control may be achieved by heterozygote detection programmes and/or prenatal diagnosis of pregnancies at risk with elective abortion of an affected foetus. The outlook for specific therapy is not encouraging at this stage.