This latter statement is illustrated in this Section by two disorders, studied through yeast as a model, for which the molecular causes have been assigned to unbalanced bioavailability of Mn2+-cofactor: Transmembrane protein 165-Congenital Disorder of Glycosylation (TMEM165-CDG) for the glycosyltransferases involved in protein maturation at the Golgi, and Friedreich ataxia for the superoxide dismutase 2 SOD2 involved in oxidative stress protection in the mitochondrial matrix. The gene discussed is SOD2; the disease is Friedreich ataxia.