Notch proteins interact with PSs and APP (Haleem et al., 2007), and play a part in the memory problems linked to AD, in post-mitotic neurons, The phenotype of PS1 deletion mice resembles that of Notch knockout mice (Donoviel et al., 1999)and the phenotype of the PS1/PS2 double knockout is even more comparable (Arumugam et al., 2006), suggesting closely related functions for these proteins. The gene discussed is PSEN2; the disease is Alzheimer disease.