Relationship between genetic risk factors and markers for Alzheimer's disease pathology

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by neuritic plaques (main constituent: beta-amyloid [A beta]) and neurofibrillary tangles (hyperphosphorylated tau protein) in the brain. Abnormalities in A beta and tau can be measured upon neuropathological examination, in cerebrospinal fluid or by PET. Etiologically, a growing body of evidence suggests that susceptibility to AD is genetically controlled. However, the precise nature of the underlying risk genes and their relation to AD biomarkers remains largely elusive. To this end, we performed a qualitative review of 17 studies (covering 47 polymorphisms in 26 genes) and investigated the potential relation between the most compelling AD risk genes and markers for A beta and tau in cerebrospinal fluid, PET imaging and neuropathological examination. Of all covered genes, only APOE and PICALM showed consistent effects on A beta but not on tau, while no obvious effects were observed for CLU, CR1, ACE, SORL and MAPT.