Gilles de la Tourette's syndrome in identical twins.

The problem we studied relates to the inheritance of Gilles de la Tourette's syndrome. The method was the investigation, including blood studies, of a pair of twins who both were affected with the syndrome. It was concluded that the twins were identical and this added to the evidence of the heritability of the disorder. The twins were affected with other but related problems of behavior; considerable similarities were found in their behavior and behavioral problems. No family history of this or tic-like disorders could be obtained. Reduction of tics occurred when haloperidol treatment began.