Similar changes were observed in AD fibroblasts after Drp1 knockdown with no effect on mitochondrial membrane potential but increased further % of cell area occupied by long mitochondria (sAD scramble 65 ± 3.4, sAD Drp1 k/d 74.4 ± 4.5; PSEN1 scramble 72.7 ± 5.3, PSEN1 Drp1 k/d 81.2 ± 5.2). The gene discussed is PSEN1; the disease is Alzheimer disease.