Fragile X syndrome is the most commonly inherited form of intellectual disability and is caused by mutations affecting fragile X mental retardation protein (FMRP, encoded by FMR1). FMRP binds RNA and is thought to regulate translation, which is of interest because protein synthesis is necessary for long-term synaptic plasticity, a process involved in forming and maintaining memory. Now, Robert and Jennifer Darnell and colleagues use high-throughput sequencing–cross-linking immunoprecipitation (HITS-CLIP) to identify 842 RNA targets of FMRP (Cell 146, 247–261, 2011 ). The authors observed significant overlap of the FMRP targets with pre- and postsynaptic proteins, suggesting a direct role for FMRP in regulating the synaptic proteome. Unexpectedly, they found that 66% of FMRP binding occurs within the coding regions of transcripts. The authors hypothesized that the number of ribosomes associated with FMRP targets would decrease when FMRP is not present. However, their results showed no differences in target mRNA-polyribosome binding between FMR1 knockout and wild-type littermates. Because the number of ribosomes on a transcript is not an accurate measurement of active translation, the authors looked at the ratio of translocating to stalled ribosomes on target transcripts. They found that ribosomes are stalled on FMRP-bound targets, but not in mice lacking FMRP function.