FXN and Friedreich ataxia: Although FRDA clinical symptoms manifest between the first and the second decade of life, patients are exposed to frataxin deficiency since development (Bürk, 2017), thus pre-symptomatic defects may contribute to determine the onset and the worsening of FRDA phenotype (Cossée et al., 2000; Santos et al., 2001; Georgiou-Karistianis et al., 2012; Rezende et al., 2016; Selvadurai et al., 2018).