Potential pharmacological treatment of fragile X syndrome during adulthood.

Fragile X syndrome (FXS) is the most common form of inherited mental retardation, characterized by moderate-to-severe mental retardation, attention deficits, and hyperactivity. This disease results from the expansion of a trinucleotide repeat (CGG) within the X-linked fragile X mental retardation 1 (FMR1) gene, which leads to the lack of the product of the FMR1 gene-fragile X mental retardation protein. Many mental disorders such as FXS and Rett syndrome are thought to originate during early developmental period, but recent findings have suggested the involvement of the processes in the adult nervous system. Here we outline our recent studies and initial clinical trials that may provide an approach to treat FXS in the adulthood.