Apoptosis in development and disease of the nervous system: II. Apoptosis in childhood neurologic disease.

The loss of cells in the human nervous system has long been known as the hallmark of incurable degenerative disease. Recent studies that began with attempts to understand cell loss during normal development have now begun to contribute to our understanding of the process of pathological cell loss. In many neurodegenerative conditions, it has become clear that apoptosis, or programmed cell death, plays a role in the diminution of cell number. In the cases of human immunodeficiency virus-associated encephalopathy and several of the hereditary neurodegenerative disorders, triggers and mediators of this process have been identified. This identification is not only the first step toward treatment of such disorders, but it also raises the possibility of exploiting this information to design targeted apoptosis-based therapies for tumors of the nervous system.