Friedreich's ataxia (FRDA) is a neurodegenerative disease caused by low levels of the mitochondrial protein frataxin. The main phenotypic features of frataxin-deficient human and yeast cells include iron accumulation in mitochondria, iron–sulfur cluster defects and high sensitivity to oxidative stress. Frataxin deficiency is also associated with severe impairment of glutathione homeostasis and changes in glutathione-dependent antioxidant defenses.