Neuronal ceroid lipofuscinsosis 1 (NCL1) (cane corso type) is a rare lysosomal storage disease affecting cane corsos. NCL1 is due to a deficiency in the Enzyme palmitoyl protein thioesterase (PPT1), which is necessary to break down certain proteins in the cells. As a result, there is an accumulation of these compounds in cells, which affects the normal function of the brain and nervous system. The first clinical symptoms were reported at approximately 8 months of age and included difficulty seeing in low light. Within two months symptoms progressed to blindness, incoordination while walking, and lethargy. These symptoms rapidly become more severe and the dog may be euthanized shortly after clinical signs appear.