Magnetic resonance imaging scans (MRI) were obtained for 14 autistic patients, aged 4 to 19 yrs, diagnosed by DSM-III criteria at the Univ of Iowa Hospitals, Iowa City, and were compared to a control group. In coronal scans, the cerebellum of autistic patients was smaller and the IVth ventricles larger whereas axial scans showed no differences from controls. The authors refer to previous reports of postmortem evidence of cerebellar pathology in autism , and CT scans showing cerebellar atrophy . The significance of cerebellar involvement in behavioral disorders is unknown. 
COMMENT. The recognition of an organically based dysfunction of the brain as a major causative factor in infantile autism is gaining favor. It may be necessary to redefine the syndrome when the causal mechanisms are better understood and when primary and secondary symptoms have been distinguished.