Whereas possible key genes (MAPT, APOE, APP, SNCA) and risk loci of APs have been identified [1,212,213,214], and recent research has unveiled essential basic mechanisms of neurodegeneration in MSA [215] and tauopathies [216,217], our knowledge about the pathogenesis of CI in this range of disorders is mainly dependent on recent neuroimaging findings, while concerning CI in APs, respective neuropathological data are rather poor. This evidence concerns the gene APOE and multiple system atrophy.