For instance, the PSEN2-mutated basal forebrain cholinergic neurons derived from induced pluripotent stem cells (iPSC) showed improved neural activity when the PSEN2 mutation was corrected with CRISPR/Cas9 [26]; the mutant PSEN2 gene is responsible for BFCN damage and is significantly correlated with early and late-onset familial Alzheimer’s disease. The gene discussed is PSEN2; the disease is familial Alzheimer disease.