Aspects of β-amyloid as a biomarker for Alzheimer's disease

Alzheimer's disease is an age-related neurodegenerative disorder that results in progressive cognitive impairment and death. The accumulation of beta-amyloid A(beta) in specific brain regions is believed by many to represent the earliest event in the pathogenesis of the disease. Here, we review the key aspects of A beta as a biomarker for Alzheimer's disease, including the pathogenicity of A beta, the possible biological functions of its precursor protein, the A beta metabolism and homeostasis, the diagnostic performance of different A beta assays in different settings and the potential usefulness of A beta as a surrogate marker for treatment efficacy in clinical trials of novel A beta-targeting drugs against Alzheimer's disease.