FXN and Friedreich ataxia: DNA methylation analysis in three regions of FXN in FRDA patients and controls using targeted bisulphite sequencing reported hypermethylation in a region upstream of the GAA repeat expansion in FXN in both brain and heart tissues, which could be responsible for the inhibition of FXN expression FRDA patients, while CpG sites downstream of the FXN GAA repeat were hypomethylated [115].