A complex chromosome rearrangement in a boy with autism.

Autism is a rare behavioral phenotype defined by a qualitative impairment in reciprocal social interaction, impairment in communication and imaginative activity, and a markedly restricted repertoire of activities and interests. It is the most severe and prototypical form of the general category of Pervasive Developmental Disorders of Childhood. Using even strict diagnostic criteria, the currently described etiologies of autism are heterogeneous, with the majority of cases continuing to be idiopathic. At present, it is not clear whether autism is merely a behaviorally defined phenotype arising from diverse etiologies or a separate category of psychological dysfunction for which some unifying etiology exists. Complex chromosome rearrangements (CCR) are rare structural abnormalities involving at least three chromosomes and three or more break-points. We report a 6.5-year-old boy with classic infantile autism and a CCR involving chromosomes 1, 7, and 21. We discuss the possible relationship of his chromosome abnormality to the etiology of his autism.