There have been many genetic polymorphisms reported to be associated with AD, such as amyloid precursor protein (APP), presenilin-1(PSEN1), presenilin-2(PSEN2) [6], apolipoprotein E (APOE) [7], [8] and sortilin-related receptor 1 (SORL1) [9]. Here, APOE is linked to Alzheimer disease.