For instance, reduced mitochondrial biogenesis and, subsequently, the number of mitochondria was reported in FRDA patient-derived cells, in FXNWT KD control cells and in brain and skeletal muscle from the KIKO mouse model (Jasoliya et al., 2017; Lin et al., 2017a,b), whereas accumulation of damaged mitochondria was observed in FRDA induced pluripotent stem cell-differentiated cardiomyocytes and cardiac Fxn conditional knockout (cKO) mice (Hick et al., 2013; Perdomini et al., 2014; Vyas et al., 2012). This evidence concerns the gene FXN and Friedreich ataxia.