FMR1 and fragile X syndrome: In the FXS, absence of FMRP has been associated to visual system defect in patients, characterized by spatiotemporal visual processing alterations (Kogan et al., 2004b; Farzin et al., 2008) as in its murine model at the retinal level (Rossignol et al., 2014; Perche et al., 2018).