[From intellectual disability to new treatment modalities of fragile X syndrome].

In 1943 a large family with X-linked mental retardation was described by Martin & Bell. This family had what we know today as fragile X syndrome, the most common inherited form of intellectual disability. Current knowledge about the specific gene, the encoded protein and the pathophysiological mechanisms involved has made it possible to develop pharmacological treatment trials. Fragile X syndrome therefore is on its way as model disorder for targeted treatments in genetic medicine, and this article reviews clinical and therapeutic aspects of the syndrome.