Demonstration of amyloid beta-protein in a 32-year-old man with progressive dementia.

We report the immunolocalization of extensive amyloid beta-protein in senile plaques, cerebrovascular amyloid deposits, neurofibrillary tangles and preamyloid in a 32-year-old man with progressive dementia not due to trisomy 21 or trauma. These amyloid deposits were non-reactive to antibodies directed against scrapie amyloid. Our data indicate that the presence of amyloid beta-protein is not limited to normal aging, Alzheimer's disease and related disorders but is also found in younger individuals with progressive dementia.