As demonstrated in iPSC-derived neural stem cells of presenilin 1 familial AD, downregulation of SDH contributes to an imbalance between mitochondrial fission, fusion, and morphology in AD hippocampus, a chronic fragmentary state of neurogenesis defects not only impelling self-renewal capacity of stem cells but also depleting stem cell pool [38, 73]. The gene discussed is PSEN1; the disease is Alzheimer disease.