Novel presenilin 1 mutation with profound neurofibrillary pathology in an indigenous Southern African family with early-onset Alzheimer's disease.

Genetically determined Alzheimer's disease (AD) is virtually unknown in Africa. We report clinicopathological findings and a presenilin 1 (PS1) mutation associated with early-onset AD in a large Xhosa family from Southern Africa. Twelve individuals spanning four generations were affected, four of whom underwent clinical and psychometric evaluation.