Mutations in three genes, amyloid precursor (APP), presenilin 1 (PSEN1) and presenilin 2 (PSEN2), play extremely important roles in the metabolism of Aβ, and these mutations have been identified as risk factors for Early Onset Alzheimer Disease (EOAD) [2]. This evidence concerns the gene PSEN1 and early-onset autosomal dominant Alzheimer disease.