The recognition of autism in children with Down syndrome--implications for intervention and some speculations about pathology.

Although autism can occur in conjunction with a range of other conditions, the association with Down syndrome is generally considered to be relatively rare. Four young boys with Down syndrome are described who were also autistic. All children clearly fulfilled the diagnostic criteria for autism required by the ICD-10 or DSM-III-R, but in each case the parents had faced considerable difficulties in obtaining this diagnosis. Instead, the children's problems had been attributed to their cognitive delays, despite the fact that their behaviour and general progress differed from other children with Down syndrome in many important aspects. The implications, for both families and children, of the failure to diagnose autism when it co-occurs with other conditions such as Down syndrome are discussed. Some speculations about possible pathological associations are also presented.