Friedreich's ataxia is an autosomal recessive cerebellar ataxia caused by triplet-repeat expansions. The causative mutation is a trinucleotide (GAA) repeat expansion in the first intron of the frataxin gene, leading to impaired transcription of frataxin. The pathological consequences of frataxin deficiency include a severe disruption of iron-sulfur cluster biosynthesis, mitochondrial iron overload coupled to cellular iron dysregulation, and an increased sensitivity to oxidative stress.