However, given that less CGG DNA methylation, more FMR1 mRNA transcription and more FMRP production in even a subset of cells in FXS patients all correlate with better clinical outcomes and differential responses to pharmacological agents (Nolin et al., 1994; Tassone et al., 1999; Jacquemont et al., 2011), even modest successes targeting these proximal events in pathogenesis may elicit meaningful effects on clinical phenotypes. This evidence concerns the gene FMR1 and fragile X syndrome.