FXN and Friedreich ataxia: Our findings show proliferation and clonogenic defects, premature neuronal differentiation and loss of neuronal complexity in E13.5 KIKO NSCs (Figures 1A–D), thus suggesting that frataxin deficiency could induce defects already during neurodevelopment in FRDA and potentially lead to impairments in the white/gray matter structure and connectivity observed in patients (Georgiou-Karistianis et al., 2012; Zalesky et al., 2014; Harding et al., 2016; Rezende et al., 2016).