Tourette syndrome

Tourette syndrome (TS) is a common, inherited neuropsychiatric disorder, characterized by the presence of chronic involuntary motor and vocal tics that wax and wane. In addition to tics, individuals with this syndrome often have a variety of concomitant psychopathologies, including obsessive-compulsive disorder, attention deficit hyperactivity disorder (ADHD), learning difficulties, and sleep abnormalities. TS is an inherited disorder, but the genetic abnormality and precise mode of transmission remain undetermined. Understanding of a role for nongenetic environmental influences is also evolving. The precise neuroanatomical localization remains unknown, but data suggest involvement of cortico-striatothalamo- cortical (CSTC) circuits. At a cellular level, the distribution of classical neurotransmitters within CSTC circuits raises the possibility that a variety of transmitters could be involved in the pathobiology of TS. Although abnormalities occur within dopaminergic systems, the precise cellular mechanism is not yet identified. An immune-mediated mechanism remains an unproven hypothesis. Active research continues, and the availability of animal models would be of major benefit.