Presenilins and β-Amyloid Precursor Protein-Proteolytically Processed Proteins Involved in the Generation of Alzheimer’s Amyloid β Peptide

Alzheimer’s disease (AD) is the most common dementia worldwide. In most of the cases, AD occurs sporadically, with an increased risk during aging. In some cases, however, mutations in three genes (see below) were found which caused early-onset familial Alzheimer’s diseases (FAD; for review, see SELKOE 1996). Furthermore, a polymorphism in the apoE allele is a major risk factor, that can significantly increase the chance of late-onset AD (ROSES 1996). A pathological hallmark of AD is the invariant accumulation of numerous senile plaques in certain areas of the brain. Senile plaques are composed of the amyloid β-peptide (Aβ), a proteolytic derivative of the β-amyloid precursor protein (βAPP; HAASS and SELKOE 1993).