Amyloid PET data from 390 patients with Mild to Moderate AD showed a mean prevalence of amyloid positivity of 95% in APOE4/4 homozygotes and 88% in APOE4 heterozygotes, compared to ~60% in non-carriers [57], indicating a problematic 40% rate of clinical misdiagnosis in APOE4 non-carriers (Figure 4). This evidence concerns the gene APOE and Alzheimer disease.