Tourette syndrome (TS) is one of the most common genetic disorders affecting man. Approximately one in 100 individuals manifests one or more of the aspects of the TS gene. This series of papers has emphasized that although motor and vocal tics are the hallmark of TS, the complete range of behavioral problems is much broader. This spectrum of behavior can be explained on the basis of the TS gene causing an imbalance of the mesencephalic-mesolimbic dopamine pathways, resulting in disinhibition of the limbic system.