Aluminium, amyloid, and Alzheimer's disease.

Alzheimer's disease is a degenerative disease characterized by the presence of numerous senile plaques and neurofibrillary tangles, primarily in the cortical areas of the brain. There is no known cause of the disease, although exposure to aluminium has been implicated by epidemiological studies and the finding of aluminium in the cerebral plaques and tangles. There is a genetic predisposition for early-onset disease, and Down's syndrome patients are particularly vulnerable. Many of the plaques contain amyloid, and a gene for amyloid precursor protein has been identified on the long arm of chromosome 21. It is possible that the amyloid plaques arise through over-expression of this gene. Since there is no specific marker for Alzheimer's disease, laboratory investigations are restricted to confirming the disease after the patient has died. Recent immunohistochemical studies have been directed towards showing the relationships between the neurones, senile plaques and neurofibrillary tangles, and the presence of amyloid and filament proteins such as tau, ubiquitin and neurofilaments.