Neuronal ceroid lipofuscinosis 8 (Australian shepherd type) is a lysosomal storage disease affecting dogs. Affected dogs lack a specific Enzyme necessary for normal metabolism. As a result, there is an abnormal accumulation of waste compounds primarily in the cells of the nervous system. Affected dogs typically present around 8 to 12 months of age with changes in behavior including increased sensitivity to sounds and a loss of learned behaviors such as housetraining and responsiveness to commands. With time, affected dogs will display various signs of progressive neurological disease including mental dullness, weakness, compulsive movements, anxiety, aggression, loss of balance, blindness, seizures and death. Death or euthanasia usually occurs by 2 years of age.