PSEN2 and Alzheimer disease: The variant disclosed in case 3, PSEN2 Arg71Trp, probably involved in protein stability and signalling pathways [18], has been found in patients with EOAD or LOAD, as well as in healthy subjects and Parkinson’s disease dementia [19, 20], and only in one large AD family it seemed to clearly segregate with the disease [21, 22].