ATP5F1A and amyotrophic lateral sclerosis: In addition, oxidative stress, impaired basal and maximal mitochondrial respiration and the direct binding of toxic PolyGR to Atp5a1, causing mitochondrial functional deficits, have recently been demonstrated in C9ORF72-ALS/FTD; however, it is not clear how early these deficits manifest in human patients [12, 42, 48].