FMR1 encodes the fragile X mental retardation protein (FMRP), an RNA-binding protein that regulates mRNA translation and synaptic function, particularly in neuronal development. FMRP contains nuclear localization signals allowing shuttling between cytoplasm and nucleus, and is involved in synaptic maturation and neuronal homeostasis 1. The protein regulates subcellular mRNA localization and cellular stress responses, with CGG repeats in the 5' UTR being essential for proper FMR1 mRNA localization and neuronal stress signaling 2. Beyond neurodevelopment, FMRP plays roles in cellular metabolism and has been implicated in cancer biology, where it may regulate glycolysis and immune cell metabolism 3. CGG repeat expansions (>200 repeats) in FMR1 cause fragile X syndrome, the most common inherited intellectual disability, characterized by mental handicap, autism-like features, and distinctive physical characteristics 4. Premutations (55-200 repeats) are associated with fragile X-associated tremor/ataxia syndrome and premature ovarian failure in women, affecting over two million people worldwide 5 6. Rare missense mutations in FMR1 can also cause fragile X syndrome with preserved post-synaptic FMRP function 7. Therapeutically, antisense oligonucleotides show promise for rescuing aberrant FMR1 splicing and restoring FMRP levels in fragile X syndrome 8. In gastric cancer, FMR1 promotes tumor cell proliferation and invasion through c-MYC signaling 9.