Neuronal Ceroid Lipofuscinosis 8 (Setter Type) is a lysosomal storage disease affecting English Setters. 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, leading to a range of nervous system disorders. Affected dogs typically present with mental dullness between 14 to 18 months of age. Progressive loss of vision, lack of muscle coordination and an abnormally stiff gait are noticed shortly thereafter. Within a few months of disease onset, seizures begin and are often the cause of death in an affected dog. Death or euthanasia usually occurs by 2 years of age.