SEMA3A and fragile X syndrome: With regard to repulsive cues, we demonstrated that fragile X mental retardation protein (FMRP), an mRNA-binding protein encoded by the causative gene of Fragile X syndrome (FXS; Bear et al., 2004; Darnell and Klann, 2013; Richter et al., 2015), is involved in Sema3A-induced growth cone collapse in a protein-synthesis-dependent manner (Li et al., 2009).