Original Paper

Journal of Autism and Developmental Disorders

, Volume 37, Issue 1, pp 12-24

First online:

A Prospective Case Series of High-risk Infants who Developed Autism

  • Susan E. BrysonAffiliated withAutism Research Centre, IWK Health Centre, Dalhousie University Email author 
  • , Lonnie ZwaigenbaumAffiliated withChild Psychiatry, Psychiatry and Behavioural Neurosciences, McMaster University
  • , Jessica BrianAffiliated withBloorview Kids Rehab
  • , Wendy RobertsAffiliated withBloorview Kids RehabUniversity of Toronto
  • , Peter SzatmariAffiliated withChild Psychiatry, Psychiatry and Behavioural Neurosciences, McMaster University
  • , Vicki RomboughAffiliated withNorth York General Hospital
  • , Catherine McDermottAffiliated withYork University

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The present paper documents the development of autism/autistic spectrum disorder in a consecutive series of nine high-risk infants followed prospectively from 6 months of age. Evidence is provided for two broadly defined subgroups: the first subgroup (n = 6) showed a decrease in IQ between 12 and 24 or 36 months (from average/near average to severe cognitive impairment), whereas the second subgroup (n = 3) continued to obtain average or near average IQs. Signs of autism emerged and/or were more striking earlier in the first subgroup. In all nine children, early impairment in social-communicative development coexisted with atypical sensory and/or motor behaviors, as did a temperamental profile marked by irritability/distress and dysregulated state. Discussion focuses on issues raised by the pattern of findings.


Autism Phenotype Early development Social Communication Cognitive Sensory Motor Temperament High-risk infants