We describe the coexistence of Asperger and Tourette syndromes (AS and TS) caused by discrete hypoxic–ischaemic necrosis of the midbrain, infrathalamic and thalamic nuclei, and striatum in an adolescent male with positive family history for tics and obsessive–compulsive disorder. Behavioural ratings, cognitive tests, and volumetric measurements of the basal ganglia were performed in the patient and five other individuals with AS–TS unassociated with MRI lesions. Cognitive deficits in attentional, executive, and visual–spatial domains were found both in the patient and control AS–TS group, though deficits were more severe in the former. MRI showed reduction of the left basal ganglia volume compared with the right in the patient, whereas the control group showed reduction of right basal ganglia volume compared with the left. It is suggested that individuals with a genetic predisposition to TS may develop AS and TS after involvement of midbrain and related components of basal ganglia-thalamocortical circuits normally implicated in the integration of emotional, cognitive, and motor functions.