1993; Thompson et al. 1993; Conjard et al. 1995; Pastoris et al. 1997; Kemp et al. 2004). Briefly, these studies showed decreased activity of mitochondrial enzymes, such as citrate synthase and hydroxyacyl‐CoA dehydrogenase, and the prolongation of phosphocreatine recovery time after exercise in skeletal muscle in patients with CKD. A recent study in mice also suggested that reduction in skeletal muscle mitochondria number would precede the onset of sarcopenia (Tamaki et al. 2014); however, no study has measured mitochondrial number in human skeletal muscle from patients with CKD. This evidence concerns the gene CS and chronic kidney disease.