Findings in skeletal muscle of women with PCOS showed no alterations in mtDNA copy number or other markers of mitochondrial content, citrate synthase (CS) and fatty acid oxidation indicated by hydroxyacyl-CoA dehydrogenase subunit beta (β-HAD) activity (Hutchison et al. 2011, Rabøl et al. 2011, Konopka et al. 2015) (Table 1). The gene discussed is CS; the disease is polycystic ovary syndrome.