Autistic-spectrum disorders in Down syndrome: Further delineation and distinction from other behavioral abnormalities

John C. Carter, George T. Capone, Robert M. Gray, Christiane S. Cox, Walter E. Kaufmann

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


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; ∼70% male), comprising: a cohort of 64 children and adolescents with DS and comorbid ASD (DS + ASD), 19 with DS and stereo-typic 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.

Original languageEnglish (US)
Pages (from-to)87-94
Number of pages8
JournalAmerican Journal of Medical Genetics, Part B: Neuropsychiatric Genetics
Issue number1
StatePublished - Jan 5 2007


  • Aberrant behavior checklist
  • Anxiety
  • Autism behavior checklist
  • Childhood disintegrative disorder
  • Dual diagnosis
  • Pervasive developmental disorder
  • Stereotypic movements
  • Trisomy 21

ASJC Scopus subject areas

  • Genetics(clinical)
  • Psychiatry and Mental health
  • Cellular and Molecular Neuroscience


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