[Autism and children with Fragile X syndrome].

Many epidemiological studies have demonstrated the exceptionally high incidence of autism in children with the fragile X syndrome, and autism is often considered a "behavioral phenotype" of this syndrome. However, the discrepancies between the results of these studies disclosed strong effects of methodological flaws and demonstrated the need for gathering clinical data. Atypical "autistic-like" behaviors were then found to be common, early symptoms of the syndrome occurring against the background of early manifestations of mental retardation. These behaviors reflect these children's exquisite reactivity to change and contact with others. Avoidance of eye contact is the most significant feature. The appropriate diagnosis is not autism but phobia of social relationships. This highly specific vulnerability, which may be inherited, probably leads some of these patients to experience the fate of autistic children. It highlights the influence of environment on the clinical course and indirectly supports the role of early specialized care.