Friedreich's ataxia (FA) is an autosomal recessive inherited ataxia caused, in >95% of cases, by a homozygous GAA.TTC trinucleotide repeat expansion within intron 1 of the FXN gene.1 This triplet expansion results in transcriptional repression of frataxin,2 a small mitochondrial protein involved in iron–sulfur cluster biosynthesis. Here, FXN is linked to Friedreich ataxia.