Specific RNAs bound by FMR1 are downregulated in Fmr1 knockout mice, implying FMR1 could not only silence gene expression but also stabilize its targets [70] FMR1 is most well known for its role in Fragile X syndrome also due to a triplet repeat expansion in the 5’ untranslated region of the FMR1 gene [71]. This evidence concerns the gene FMR1 and fragile X syndrome.