The biomarker of amyloid peptide and the Alzheimer's disease risk (BALTAZAR) study found that the plasma Aβ was associated with cognitive performance, apolipoprotein E (APOE)-ε4 status, and CSF Aβ in cross-sectional analyses (Hanon et al., 2018). Here, APOE is linked to early-onset autosomal dominant Alzheimer disease.