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Chapter 9 Candidate BioMarkers of Alzheimer ’ s Disease

Alzheimer’s disease (AD) is a neurodegenerative disorder of the central nervous system characterized by a progressive loss of short-term memory accompanied by a gradual loss of cognitive functions (Ross et al., 2004). AD is among the most frequently encountered diseases in aging societies with an estimated 5million people in the United States and 17 million people worldwide suffering from the disease. It is expected that these numbers will quadruple by the year 2040, by which 1 out of 45 Americans will be affected, leading to a considerable public health burden (Fratiglioni et al., 1999). AD pathogenic mecha‐ nisms contributing to neuronal loss and brain dysfunction are still unclear. However, remarkable advances have taken place in understanding of both the genetics and molecular biological aspects of the intracellular processing of amyloid and tau and the changes leading to the pathologic formation of extracellular amyloid plaques and the intraneuronal aggregation of hyperphosphorylated tau into neurofibrillary tangles. This progress in our understanding of the molecular pathology has set the stage for clinical‐ ly meaningful advances in the development of biomarkers.