Dogs suffer from many of the same hereditary progressive neurodegenerative diseases that occur in humans. Among these are a group of disorders designated the neuronal ceroid lipofuscinoses (NCLs). In people these diseases are characterized by apparently normal development followed by progressive declines in cognitive and motor functions, loss of vision, seizures, and in most cases premature death [1]. These clinical signs are accompanied by progressive degeneration of the central nervous system and usually the retina as well.