Furthermore, IUGR muscle exhibited reduced activity of pyruvate dehydrogenase and citrate synthase enzymes that generate Krebs cycle intermediates, as well as increased expression of (inhibitory) pyruvate dehydrogenase kinase and impaired function of Electron Transport Chain Complex I (Brown et al., 2015; Pendleton et al., 2019; Stremming et al., 2022). The gene discussed is CS; the disease is fetal growth restriction.