We compared APOE-E4/E4, -E3/E4 to APOE-E3/E3 but not to carriers of the APOE-E2 allele because the relationship between the APOE-E2 isoform and AD neuropathology is ambiguous and not thoroughly investigated to date (Berlau et al., 2009). The gene discussed is APOE; the disease is Alzheimer disease.