Early-onset Alzheimer’s disease (EOAD), that accounts for ∼5% of Alzheimer’s disease cases, can be caused by autosomal dominant mutations that may be inherited or occur de novo in the APP,1 presenilin 1 (PSEN1)2 or presenilin 2 (PSEN2) genes.3 The gene discussed is PSEN1; the disease is early-onset autosomal dominant Alzheimer disease.