Fragile X syndrome: Assessment and treatment implications

Fragile X syndrome (FraX) is the most common known cause of inherited mental impairment. FMR1 gene mutations, the cause of FraX, lead to reduced expression of FMR1 protein and an increased risk for a particular profile of cognitive, behavioral, and emotional dysfunction. The study of individuals with FraX provides a unique window of understanding into important disorders such as autism, social phobia, cognitive disability, and depression. This review highlights the typical phenotypic features of individuals with FraX, discussing the apparent strengths and weaknesses in intellectual functioning, as evidenced from longitudinal follow-up studies. It also discusses recent neuroanatomic findings that may pave the way for more focused disease-specific pharmacologic and behavioral interventions. This article describes the results of an open-label trial of the antiglucocorticoid medication, mifepristone, that the authors have recently conducted in boys and men with FraX, as well as other medication trials designed to target symptoms associated with FraX It also describes some recent behavioral interventions that were conducted in the authors' laboratory.