Dementia, pyramidal system involvement, and leukoencephalopathy with a presenilin 1 mutation.

The authors describe four members of a family with a novel P284S presenilin 1 mutation presenting a clinical phenotype characterized by early-onset dementia, paratetraparesis, dysarthria, dysphagia, and marked involvement of brain white matter. The distinctive clinical and MRI findings in the family studied extend the phenotypic spectrum of dementia associated with mutation of the PS1 gene.