FMR1 and fragile X syndrome: Translation of the mRNAs for NLGN1, NLGN2, and NLGN3 is negatively regulated by Fragile X mental retardation protein (FMRP), loss of this translational repressor, FMRP, leads to Fragile X syndrome, associated with ASD (Joo & Benavides, 2021).