The role of fragile X mental retardation protein in major mental disorders

Fragile X mental retardation protein (FMRP) is highly enriched in neurons and binds to approximately 4% of mRNAs in mammalian brain. Its loss is a hallmark of fragile X syndrome (FXS), the most common form of mental retardation. In this review we discuss the mutation in the fragile X mental retardation-1 gene (FMR1), that leads to FXS, the role FMRP plays in neuronal cells, experiments from our own laboratory that demonstrate reductions of FMRP in additional psychiatric disorders (autism, schizophrenia, bipolar disorder, and major depressive disorder), and potential therapies to ameliorate the loss of FMRP. This article is part of a Special Issue entitled ‘Trends in Neuropharmacology: In Memory of Erminio Costa’. ► FXS is caused by loss of function of the FMR1 gene and consequent loss of FMRP. ► FMRP is an RNA binding protein that binds to 4% of all RNAs expressed in the brain. ► FMRP is reduced in brains of subjects with major mental disorders.