Behavioral aspects of Angelman syndrome: a case control study

Angelman syndrome (AS) is a rare congenital disorder characterized by impairments in intellectual, neurological and motor functioning and a postulated behavioral profile. This study compared behavioral characteristics of 62 individuals with genetically confirmed AS and 29 individuals with presumed AS from clinical features, with a control group of young persons with intellectual disability (ID) derived from an Australian epidemiological register. Twelve behavioral items from the developmental behavior checklist (DBC) were used for this comparison. The groups were matched for chronological age, gender, and level of ID. In the AS group, significant differences were found for 10 behaviors, with poor attention span and impulsivity being less common, and overactivity/restlessness, chewing or mouthing objects, eating non-food items, gorging food, food fads, fascination for water, hand flapping and sleep disturbance being more common. Interestingly, there was no difference in prevalence of unprovoked laughter. Comparison of the results of the genetically confirmed with the genetically unconfirmed AS cases showed no significant differences between individual behavior prevalence. These findings show that a "behavioral phenotype" of AS can be distinguished from others of similar level of ID, but it is different from that hitherto published. Abnormal food related behaviors, hyperactivity, fascination for water, hand flapping, and sleep disturbance should be included in a "behavioral phenotype" for AS. Apart from hyperactivity, "ADHD-type" behaviors are not more characteristic of AS than in ID generally. Therefore, the Consensus Criteria for the diagnosis of AS need to be reviewed.