New insights into the molecular pathophysiology of fragile X syndrome and therapeutic perspectives from the animal model

Fragile X syndrome is the most common monogenetic form of intellectual disability and is a leading cause of autism. This syndrome is produced by the reduced transcription of the fragile X mental retardation (FMR1) gene, and it is characterized by a range of symptoms heterogeneously expressed in patients such as cognitive impairment, seizure susceptibility, altered pain sensitivity and anxiety. The recent advances in the understanding of the pathophysiological mechanisms involved have opened novel potential therapeutic approaches identified in preclinical rodent models as a necessary preliminary step for the subsequent evaluation in patients. Among those possible therapeutic approaches, the modulation of the metabotropic glutamate receptor signaling or the GABA receptor signaling have focused most of the attention. New findings in the animal models open other possible therapeutic approaches such as the mammalian target of rapamycin signaling pathway or the endocannabinoid system. This review summarizes the emerging data recently obtained in preclinical models of fragile X syndrome supporting these new therapeutic perspectives.AB-G was recipient of a predoctoral fellowship (Ministerio de Educación y Cultura) and supported by “Investments for the future” Programme IdEx Bordeaux (ANR-10-IDEX-03-02, French National Research Agency). Related research on the subject was supported by grants from FRAXA Research Foundation (A.O.), Jérôme Lejeune Foundation (A.O.), Ministerio de Ciencia e Innovación (#BFU2012-33500 to A.O., #SAF2011-29864 to R.M.); Instituto de Salud Carlos III (RD06/0001/0001 to R.M.); PLAN E (Plan Español para el Estímulo de la Economía y el Empleo); Generalitat de Catalunya (SGR-2009-00731 to R.M.); ICREA (Institució Catalana de Recerca i Estudis Avançats) Academia to R.M