The Psychiatric Presentation of Fragile X: Evolution of the Diagnosis and Treatment of the Psychiatric Comorbidities of Fragile X Syndrome

The Psychiatric Presentation of Fragile X: Evolution of the Diagnosis and Treatment of the Psychiatric Comorbidities of Fragile X Syndrome: Fragile X syndrome (FXS) is the leading inherited cause of mental retardation and autism spectrum disorders worldwide. It presents with a distinct behavioral phenotype which overlaps significantly with that of autism. Unlike autism and most common psychiatric disorders, the neurobiology of fragile X is relatively well understood. Lack of the fragile X mental retardation protein causes dysregulation of synaptically driven protein synthesis, which in turn causes global disruption of synaptic plasticity. Thus, FXS can be considered a disorder of synaptic plasticity, and a developmental disorder in the purest sense: mutation of the FMR1 (fragile X mental retardation 1) gene results in abnormal synaptic development in response to experience.