APOE and Alzheimer disease: In the analysis of the APOE polymorphism, no differences in genotype distribution according to delusion symptom was shown, despite a non significant lower frequency of the APOE ε2 allele in AD patients with delusions (0.032 vs. 0.070, p = 0.041; OR = 0.415, 95% CI = 0.166–1.038).