Forty children with dyskinetic movement disorders and associated psychiatric disorders following streptococcal infections seen between 1999 and 2002 are reported from the Institute of Child Health and Great Ormond Street Hospital for Children, London, UK. Dyskinesias included chorea in 20 patients (65% female), motor tics (16 [69% male]), dystonia (5), tremor (3), stereotypies (2), opsoclonus (2), and myoclonus (1). Psychiatric disorders were diagnosed in 62.5%, compared to an 8.9% expected incidence in UK children. These included emotional disorders in 47.5%, including obsessive-compulsive disorder (27.5%), anxiety (25%), and depressive episodes in 17.5%. Conduct disorder occurred in 27.5% and hyperkinetic behavior in 15%. A family history of dyskinesias, psychiatric disorders, and post-streptococcal autoimmune disorders was common. Symptoms continued in 72.5% at a mean follow up of 2.7 years. 
COMMENT. The authors have extended their earlier report of a postinfectious autoimmunity against basal ganglia associated with an encephalitis lethargica syndrome (Ped Neur Briefs Jan 2004;18:1-2)  to emphasize the association of dyskinesias and psychiatric disorders following streptococcal infection in children. In a further article, they have demonstrated the utility of anti-basal ganglia (neuronal) antibodies (ABGA), using Western immunoblotting, as a potential diagnostic marker in post-streptococcal neurological disorders . That an autoimmune mechanism may underlie a proportion of adult cases of atypical movement disorders is suggested by the finding of ABGA in 42 (65%) of 65 consecutive patients seen at the Institute of Neurology, Queen Square, London . Multiple factors may be involved in the mechanism of post-streptococcal dyskinesias.