FOXH1 and Friedreich ataxia: Furthermore, the low expression of CTCF (the proposed regulator of FAST-1) in FRDA patients, and the corresponding accumulation of FAST-1 in FRDA patients, underscores the role of antisense transcription in the formation of heterochromatin (Cho et al., 2005; De Biase et al., 2009; Hahn et al., 2010).