Molecular genetic advances in neurodegenerative disorders.

Advances in molecular genetics have had a major impact on our understanding of the pathogenesis of neurologic disorders. This article discusses molecular genetic contributions to our knowledge of Huntington's disease, amyotrophic lateral sclerosis, and Alzheimer's disease, as well as their implications for diagnosis and treatment. Specific, sensitive testing for Huntington's disease is now possible; elucidation of the pathogenesis of familial amyotrophic lateral sclerosis has been achieved and has launched promising drug trials; and the heterogeneity and pathogenetic complexity of Alzheimer's disease have been revealed.