title: Autistic-spectrum disorders in Down syndrome: further delineation and distinction from other behavioral abnormalities.
abstract: The present study extends our previous work characterizing the behavioral features of autistic-spectrum disorder (ASD) in Down syndrome (DS) using the Aberrant Behavior Checklist (ABC) and Autism Behavior Checklist (AutBehav). We examined which specific behaviors distinguished the behavioral phenotype of DS + ASD from other aberrant behavior disorders in DS, by determining the relative contribution of ABC and AutBehav subscales and items to the diagnosis of ASD. A total of 127 subjects (aged 2-24 years; mean age: 8.4 years; approximately 70% male), comprising: a cohort of 64 children and adolescents with DS and co-morbid ASD (DS + ASD), 19 with DS and stereotypic movement disorder (DS + SMD), 18 with DS and disruptive behaviors (DS + DB), and 26 with DS and no co-morbid behavior disorders (DS + none) were examined using the aforementioned measures of aberrant behavior. We found that subjects with DS + ASD showed the most severe aberrant behavior, especially stereotypy compared to DS + none and lethargy/social withdrawal and relating problems compared to DS + SMD. Specifically, relatively simple stereotypic behavior differentiated DS + ASD from DS + DB, whereas odd/bizarre stereotypic and anxious behavior characterized DS + ASD relative to DS + SMD and DS + none. Additionally, in a subset of subjects with DS + ASD and anxiety, social withdrawal was particularly pronounced. Overall, our findings indicate that a diagnosis of DS + ASD represents a distinctive set of aberrant behaviors marked by characteristic odd/bizarre stereotypic behavior, anxiety, and social withdrawal.
authors.affiliation: Center for Genetic Disorders of Cognition & Behavior, Kennedy Krieger Institute, Baltimore, Maryland 21211, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Carter
authors.forename: George T
authors.initials: GT
authors.lastname: Capone
authors.forename: Robert M
authors.initials: RM
authors.lastname: Gray
authors.forename: Christiane S
authors.initials: CS
authors.lastname: Cox
authors.forename: Walter E
authors.initials: WE
authors.lastname: Kaufmann
mesh_terms: D000293:Adolescent; D000328:Adult; D001007:Anxiety / Q000150:complications / Q000235:genetics; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000150:complications / Q000235:genetics; D001321:Autistic Disorder / Q000150:complications* / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D003071:Cognition; D015331:Cohort Studies; D004314:Down Syndrome / Q000150:complications* / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D012920:Social Behavior Disorders / Q000150:complications / Q000235:genetics; D019956:Stereotypic Movement Disorder / Q000150:complications / Q000235:genetics