PSEN1 and Alzheimer disease: Aberrant elevated phospho-eIF2α has been found in sporadic AD patients’ brains [34, 54–59] and in different transgenic mouse models of AD, including APP/PS1 [34, 60, 61], Tg2576 [56, 62] and 5XFAD [57, 62, 63], (but see [43]).