Genetically engineered animal models of human neurodegenerative diseases.

The influence of a single gene, engineered to be normally or abnormally expressed, can be evaluated in vivo through the development of transgenic animals. Application of this approach in the study of human neurological problems is contributing to an increased understanding of the pathogenic components operative in a variety of disorders. These include Alzheimer's disease, prion encephalopathies, motor neuron disease such as amyotrophic lateral sclerosis, and fragile X syndrome, as well as a number of viral-mediated neurological disorders. These transgenic animals can also serve as models to investigate the possible involvement of additional genetic and environmental factors on the disease state. Moreover, transgenic animals can be used in the development of intervention strategies. The application of this powerful and increasingly popular tool to investigate neurodegenerative disorders is reviewed.