PSEN2 and early-onset autosomal dominant Alzheimer disease: Pathogenic variants in APP, PSEN1 and PSEN2 were thought to exclusively cause early onset familial AD (EOFAD) [5], but the screening of some late onset families and even sporadic cases, revealed that the contribution of familial genetic variants in APP, PSEN1 and PSEN2 in idiopathic cases cannot be neglected [6–8].