This is a multidisciplinary research program to study neurological diseases affecting brain development, both in humans and in experimental animals, and the basic neurobiological process in developing brain. It represents a continuation of long-standing combined efforts of clinicians and basic scientists covering a broad range of discplines, including pediatric neurology, clinical psychology, histology and electron microscopy, and biochemistry. The program consists of two major sections, one involving human patients, and the other, basic experimental studies. The program is concerned with inherited metabolic and developmental disorders, including sphingolipidoses, Kinky hair syndrome and related diseases. Collaborative studies among clinicians, morphologists and biochemists are planned for understanding the molecular basis of these diseases. The Golgi study of neuronal processes in normal and pathological brain development is an important new component of the program. Studies of appropriate experimental models and of fundamental processes of brain development complement the studies of human patients. This organization is based on our continuing and successful philosophy that meaningful understanding of human pathological conditions cannot be achieved without suppoort of relevant fundamental studies and that progress in studies of diseases in turn often provides new insight into the basic normal processes.