Amyloid precursor protein(APP) ,with 32-amino acid protein (about 35 kDa), is part of a super-family of transmembrane and secreted proteins. It appears to have a number of roles, including regulation of haemostasis and mediation of neuroprotection. APP undergoes alternative splicing, resulting in several isoforms . Proteolytic cleavage of amyloid precursor protein leads to the formation of the 4 kDa amyloid beta/A4 protein, which is present in human platelets. APP is also involved in the formation of neurofibrillary tangles and plaques that characterize the senile plaques of Alzheimer patients.