Increased A beta 42(43)-plaque deposition in early-onset familial Alzheimer's disease brains with the deletion of exon 9 and the missense point mutation (H163R) in the PS-1 gene.

Cerebral amyloid deposition is a neuropathological hallmark for Alzheimer's disease (AD). Immunohistochemical analysis of two A beta species (A beta 42/43 and A beta 40) deposition was undertaken using the carboxyl end-specific antibodies to determine the molecular alteration of these species in the brains of patients whose presenilin 1 (PS-1) gene, the major causative gene for the early-onset familial AD, bears the point mutation (H163R) and the deletion of exon 9. We found a marked increase in A beta 42-plaque deposition in brains of patients with PS-1 mutations compared with that in brains of those with sporadic AD. The results of immunohistochemical analysis indicate that both mutation and deletion in the PS-1 gene promote deposition of A beta 42-plaques indicating the pathological association of PS-1 and betaAPP/A beta 42 in early-onset familial AD.