To assess the influence of the ApoE4 genotype on CSF Ng and α-Syn, we stratified AD patients into two subgroups: ApoE 4(+) (i.e., patients carrying the ApoE ε4 allele, both in homo- and heterozygosis; n = 19) and ApoE 4(−) (i.e., patients carrying other ApoE alleles; n = 50). Here, APOE is linked to Alzheimer disease.