PSEN2 and Alzheimer disease: Katayama et al., in their study, reported that mutation in presenilin-1 (PS1), and induction of high-mobility group A1a (HMGA1a) protein by Presenilin-2 (PS2) isoform, i.e., PS2V, along with the activation of Caspase-4 are all responsible for the neuronal cell death in AD.