Alzheimer's disease is a condition marked by the deterioration of mental function. The disease usually begins in late middle life and results in death in 5 to 10 years. Patients with Alzheimer's disease typically suffer from memory loss, confusion, and disorientation. The condition has become a major medical and social problem in the United States because of the increasing number of people living beyond the age of 65. The actual cause of Alzheimer's disease is unknown.

Researchers believe that Alzheimer's disease, or at least a portion of cases, may be an inherited condition. As a result, many new techniques have been developed to study the genetic causes of Alzheimer's disease and other neurological disorders. Many of these genetic techniques require blood samples and a family pedigree. A pedigree is a chart, similar to a family tree, that shows a patient's family history.

The purpose of this study is to collect family and psychosocial information, blood, and biopsy samples from patients with neurological diseases, their families, and normal volunteers. This information gathered will be used to learn more about diseases that affect the brain.