The hypercholesterolemia drug 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor lovastatin, which inhibits the mevalonate pathway and Ras activation upstream of ERK1/2, was beneficial in preclinical FXS models (Osterweil et al., 2013; Asiminas et al., 2019; Muscas et al., 2019), but did not succeed well in clinical trials (Çaku et al., 2014; Thurman et al., 2020; Champigny et al., 2022). This evidence concerns the gene MAPK3 and fragile X syndrome.