Alzheimer's disease.

Alzheimer's disease is the most important cause of dementia, but its cause remains unknown. Amyloid plays a dominant role in many current theories of the pathogenesis, although it is still not clear if its deposition is the trigger or the result of other processes causing cell death. An association between sporadic and familial late-onset Alzheimer's disease and polymorphisms of apolipoprotein E located on chromosome 19 suggests a new genetic model of this condition. Head trauma and substandard education have been consistently associated with increased risk, whereas the use of anti-inflammatory agents may reduce the risk of developing Alzheimer's disease. Functional imaging may have developed to the point of making an important contribution to our understanding of the neural networks impaired in Alzheimer's disease, but it has not yet provided a diagnostic marker. The limited benefit of tacrine as an approved form of treatment is still being defined, but no new therapies have emerged.