Mutations in the amyloid precursor protein (APP) gene (APP), presenilin-1 (PS1), and presenilin 2 (PS2) genes (PSEN1, PSEN2) can lead to early-onset familial Alzheimer’s disease (fAD) characterized by symptom onset before the age of 65 [3]. The gene discussed is PSEN2; the disease is familial Alzheimer disease.