C9orf72 and frontotemporal dementia: Several disease-causing genes associated with brain homeostasis, including chromosome 9 open reading frame 72 (C9ORF72), microtubule-associated protein tau (MAPT), progranulin (GRN), and fused-in-sarcoma (FUS), have been linked to the development of FTD and aberrant mitochondrial function [48].