Fragile X syndrome (OMIM #300624), the major cause of inherited intellectual disability among men, is due to deficiency of the synaptic function regulator FMR1 protein (FMRP; UniProt Q06787), encoded by the FMRP translational regulator 1 (FMR1, OMIM #*309550) gene. This evidence concerns the gene FMR1 and fragile X syndrome.