Furthermore, mitochondrial swelling, measured by mitochondrion permeability transition pore (MPTP) kinetics, has been observed in the skeletal muscle of patients with chronic obstructive pulmonary disease, and abnormalities in the activity of the MPTP may be involved in the increased susceptibly of muscle injury, increased reactive oxygen species production and enhanced cytochrome C release observed in these patients [37]. The gene discussed is CYCS; the disease is chronic obstructive pulmonary disease.