The highest goal of science, as it is applied to medicine, is to alleviate human suffering. Current research on genes and the human brain focuses on diseases and disorders of the central nervous system, with a broader perspective of obtaining an understanding of how the brain works and how it can be helped to work better if there is a problem. The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited disorders that cause progressive neurological dysfunction. The clinical characteristics may vary from individual to individual and include retinal degeneration, which can lead to progressive blindness, cognitive and/or motor dysfunction, and epilepsy. These disorders mainly affect infants and children; rarely adults. In the past, the NCLs were diagnosed and categorized into four forms on the basis of age-at-onset and ultrastructural findings.