Tourette syndrome (TS) is a problem of the nervous system that was first described by the French neurologist, Gilles de la Tourette, more than 125 years ago.
The major symptom is tics. Tics are sudden, brief, involuntary or semi-voluntary movements (motor tics) or sounds (vocal tics).
To make a diagnosis of TS, a person must have many motor tics and at least one vocal tic, almost every day for more than a year.
A person who has a tic does not necessarily have TS. Tics are, in fact, relatively common. They occur most often from age 9 to 11, in up to 10% of children. In contrast, the full Tourette syndrome is much less common, occurring in less than 1%. Boys are affected three times more often than girls. TS is also more common in children with autism or Asperger syndrome.
Tourette syndrome has a strong genetic component, although the genetic mechanisms are not yet known. As with many other illnesses, TS will probably not turn out to be a single condition with one cause. Rather, it is likely to have multiple causes.
If someone has TS, the chance that someone else in the immediate family has tics is about 25%. Up to 90% of identical twins are affected. Environmental factors probably play a role in the development of TS (for example, stress or infection), but these causes are not well defined.
TS often is accompanied by other behavioral or emotional problems, such as attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder, learning difficulties, sleep problems, depression and anxiety.