Precursor of Alzheimer’s Disease (PAD) A4 Amyloid Protein

Alzheimer’s disease affects 1% of the population of the Western world and 100% of aged individuals with Down’s syndrome. It is characterized by neuronal dysfunction and depositions of. amyloid A4 protein (β-protein) in the form of intracellular neurofibrillary tangles, extracellular plaques and cerebrovascular amyloid. Amyloid A4 is a self-aggregating protein that consists of 42–43 residues. “Reverse genetics” based on the sequence of amyloid A4 protein has indicated that the amyloid protein is encoded as part of a larger protein by a gene on chromosome 21. Recent cloning studies have indicated that the amyloid precursor gene encodes at least three alternatively spliced products.