The association between autism and fragile X syndrome

The fragile X syndrome in males presents with a number of autistic features, including poor eye contact, hand-flapping, hand-biting, attentional deficits, tactile defensiveness, perseverative speech, and difficulties with social interactions, although a pervasive lack of relatedness is usually not present. There exists, therefore, a significant degree of overlap between autism and fragile X syndrome. Approximately 7% of autistic males havethe fragile X syndrome, and preliminary work suggests a similar prevalence in autistic females. We hypothesize frontal lobe dysfunction in fragile X syndrome interfering with sensory associations, integration, and inhibition which leads to autistic features. Preliminary neuropsychological studies in fragile X females document frontal lobe deficits.