Zamani and colleagues reported the best treatment response to rivastigmine in AD patients with PSEN2 +A/−A genotype, alone or in combination with APOE ε3/ε3 or APOE ε4/ε4 genotype, while individuals with combined PSEN2 +A/+A and APOE ε3/ε4 genotypes had the worst response to treatment [242]. This evidence concerns the gene APOE and Alzheimer disease.