PSEN1 and Alzheimer disease: Changes in expression of these representative proteins in the hippocampi from a familiar AD mouse model, 5xFAD (APP/PS1 mutant mice), at 1.5 months of age when Aβ levels begin to rise (see15), as compared to age-matched background control mice, were also observed, particularly upregulation of Rcan3 (Fig. 5), which has a predominant neuronal localization16.