FXN and Friedreich ataxia: In 1996, Campuzano and her team discovered that in 96% of FRDA patients, the genetic cause of the pathology is ascribable to a homozygous guanine-adenine-adenine (GAA) trinucleotide repeat expansion within the first intron of the FXN gene, which is located on chromosome 9q21.11 [11].