The case history of a 3-year-old boy without speech and who met 10 criteria of an autistic condition (DSM-IV) (American Psychiatric Association 1994) is reported. Psychometric evaluation, excluding the verbal scale, resulted in an IQ score of 56. The cytogenetic study showed a 20/22 translocation and an interstitial deletion within the region 22q11: 45,XY, -22, +der(20), t(20;22) (q13.3;q11.2), which was confirmed by fluorescence in situ hybridisation (FISH). Although deletions at 22q11 are responsible for the DiGeorge syndrome; clinical, metabolic, and neurological image studies of the patient were inconsistent with this syndrome. In the clinical examination the patient presented with a mildly dysmorphic facies, pectus excavatum, and a short thumb. A 99mTc HMPAO brain perfusion SPECT showed a hypoperfusion of the left temporoparietal cortex. As there have been no previous reports of autistic patients with abnormalities involving both chromosomes 20 and 22, these findings merit some discussion either as a possible cause of autism or as accompanying factors.