VARIABILITY OF BETA-AMYLOID PROTEIN DEPOSITED LESIONS IN DOWNS-SYNDROME BRAINS

An immunohistochemical study was carried out on the brains of 7 adult Down's syndrome cases (ages 31 to 62) using antibodies to beta-protein , beta-amyloid protein precursor and tau-protein. Variable forms of be ta-protein deposited lesions (including senile plaques and cerebrovasc ular amyloidosis) were observed in extensive areas of the neocortex of all cases and coexistence of both beta-protein amyloid fibrils and be ta-amyloid protein precursors was also seen in some of these lesions. Moreover, 3 cases at an advanced stage showed a few plaque-like lesion s with beta-protein immunoreactivity in the white matter. The followin g temporal morphological change is suggested for the pathogenesis of A lzheimer's disease: senile plaque undergo sequential structural change s and beta-protein amyloid deposits in the form of ''early plaque'' pr ecede the development of tau-immunoreactive neurofibrillary degenerati on.