APOE and Alzheimer disease: We find the described negative association between the plasma apoE and CSF α-synuclein levels (absent when accounting for APOE genotype) very intriguing especially when considering the frequently reported co-occurrence of AD and Lewy body pathology (reviewed in [84, 85]) and the recently reported association between the APOE ε4 allele and α-synuclein pathology [86, 87].