MOLECULAR GENETICS OF ALZHEIMER DISEASE

Alzheimer disease (AD) is characterized histopathologically by the intraneuronal accumulation of paired helical filaments (PHFs) composed of abnormal tau proteins and extracellular deposits of an amyloid peptide (A ) in plaques (1). AD plaques are round, spheric structures, 15 to 20 M in diameter, consisting of a peripheral rim of abnormal neuronal processes and glial cells surrounding a core of deposited material. Several associated proteins have been identified in the plaques including heparan sulfate proteoglycans (2), apolipoprotein E (Apo E), and -antichymotrypsin (3), as well as metal ions (4).