Causative gene mutations have been associated with autosomal dominant familial AD (FAD), such as amyloid precursor protein (APP) and presenilin 1 and 2 (PS1, PS2), and genetic risk factors such as Apolipoprotein E (APOE), sortilin‐related receptor with type‐A repeats (SORL1), and so forth; however, FAD accounts for less than 5% of all AD cases.4, 5, 6, 7. Here, APOE is linked to Alzheimer disease.