Head circumference in autism and other pervasive developmental disorders.

Recent studies have found that an unexpectedly large proportion of autistic children have large heads. Anthropometric measures of consecutive clinic attenders with pervasive developmental disorder (PDD), other psychiatric or language disorders were analysed. Similar data were obtained from two schools for language disordered children. These data, combined with those from previous studies, indicate that about one-third of children with PDD have macrocephaly based on current percentile charts; this rate was significantly higher than in children with language disorder alone. The finding was not a consequence of recognizable medical disorders and suggests that PDD is sometimes associated with abnormal physical development.