PSEN2 and early-onset autosomal dominant Alzheimer disease: Alzheimer's disease (AD) is considered one of the most frequent diseases and here we contemplate multiple factors that trigger its onset [1, 2], such as genetic disposition due to variations present in the genes that translate proteins such as presenilin-1 (PS1), presenilin-2 (PS2), and amyloid precursor protein (APP) [3–5].