PSEN1 and Alzheimer disease: To support this notion, Soejima and associates examined the aggregation of Aβ oligomers, toxic turn Aβ (at positions 22 and 23), and Aβ in brains of AD patients and triple transgenic (3 × Tg)-AD mice, as well as in SH-SY5Y cells transfected with PSEN1 gene (participates in the formation of Aβ) [72].