Sex differences in underlying AD pathology have also been reported, with autopsy [9], neuroimaging [10], and cerebrospinal fluid (CSF) [11, 12] studies reporting higher levels of pathological tau (referred here simply as “Tau”) in women versus men who are either diagnosed with or are at-risk for AD by way of the APOE4 allele or clinically significant beta-amyloid (Aβ) plaque deposition in the brain. The gene discussed is APOE; the disease is Alzheimer disease.