Many neurodegenerative disease-associated aggregation-prone proteins, such as α-synuclein (Devi et al., 2008), FUSP525L (Deng et al., 2018; Deng et al., 2015), TDP-43 (Wang et al., 2016), amyloid beta (Hansson Petersen et al., 2008), and C9ORF72-associated poly(GR) dipeptide (Choi et al., 2019), are detected in mitochondria of human patients or disease models and impair mitochondrial functions. The gene discussed is C9orf72; the disease is neurodegenerative disease.