Decreased enzymatic activity of aconitase and complexes of the ETC have been reported from cardiac biopsies of patients (Rötig et al., 1997), as well as in MCK conditional heart knockout mice (Puccio et al., 2001); mitochondrial ATP production was decreased in 31P-MRI analyses of the skeletal muscle (Lodi et al., 1999) and hearts (Lodi et al., 2003) of FRDA patients, and the activity of aconitase was decreased in the hearts of a murine frataxin knockdown model (Chandran et al., 2017). The gene discussed is CKM; the disease is Friedreich ataxia.