APOE and Alzheimer disease: Also, there is evidence of the relation between ALF and early markers of AD, including subjective complaints, autosomal dominant AD mutation carriers, APOE E4 carriers, and abnormal levels of CSF Aβ42 and CSF Aβ42/ptau ratio (Tort-Merino et al., 2017, 2021a,2021b; Reiman, 2018; Weston et al., 2018; Zimmermann and Butler, 2018; Butler et al., 2019).