Previous studies showed reduced histone acetylation and increased tri-methylation of H3K9 and H3K27 in the FXN locus as hallmarks of FRDA.20 We used ChIP to assess these key histone modifications in fully differentiated sensory neuronal cultures (Fig. 1) obtained from nine hiPSC lines (two CTs, five FRDA and the ISO CTs lines IcFA4 and IcFA5), in a region spanning from the first exon of the gene to 880 bp downstream of the GAA expansion18 (Fig. 1C). This evidence concerns the gene FXN and Friedreich ataxia.