Current status of genetic studies of Gilles de la Tourette syndrome.

Gilles de la Tourette syndrome (TS) is a familial, neuropsychiatric disorder characterized by chronic, intermittent motor and vocal tics. Despite strong evidence for a genetic basis of this disorder from family, twin, and adoption studies, no convincing evidence for genetic linkage has been reported. Numerous groups world-wide have searched for genetic susceptibility factors for TS, testing specific candidate genes in neurotransmitter systems as well as DNA markers with known locations. Several factors may complicate the search for genes for this disorder, including diagnostic uncertainties, definition of the TS phenotypic spectrum as it relates to genetic susceptibility, assortative mating, genetic heterogeneity, and unclear mode of inheritance. In this article, we review the evidence for the genetic basis of TS and the current status of genetic studies.