Tourette syndrome (TS) is a childhood-onset neurobehavioral disorder characterized by the presence of multiple motor and at least one phonic tic.
- Tics are sudden, brief, repetitive, stereotyped motor movements (motor tics) or sounds (phonic tics) produced by moving air through the nose, mouth, or throat.
- Patients can suppress their tics, but this often causes inner tension that eventually results in more forceful tics.
- System(s) affected: nervous
- Average age of onset: 7 years with greatest tic severity between 10 and 12 years (1)
- Male > female (3:1); heterogeneous disorder but non-Hispanic whites (2:1) compared with Hispanics and/or blacks
0.77% overall in children (1.06% in boys, 0.25% in girls)
Etiology and Pathophysiology
Abnormalities of dopamine neurotransmission and receptor hypersensitivity, most likely in the ventral striatum, play a primary role in the pathophysiology. May involve dysfunction of basal ganglia–thalamocortical circuits, likely involving decreased inhibitory output from the basal ganglia, which results in an imbalance of inhibition and excitation in the motor cortex
- Thought to result from a complex interaction between social, environmental, and multiple genetic abnormalities
- Controversial pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS); TS/OCD cases linked to immunologic response to previous group A β-hemolytic Streptococcus (GABHS)
- Predisposition: frequent familial history of tic disorders and OCD
- Recent studies suggest polygenic inheritance with evidence for a locus on chromosome 17q; sequence variants in SLITRK1 gene on chromosome 13q also are associated with TS.
- Risk of TS among relatives: 9.8–15%
- Low birth weight, maternal stress, nausea/vomiting in 1st trimester, maternal smoking (2)
Commonly Associated Conditions
- OCD (28–67%), ADHD (50–60%), conduct disorder, learning disabilities (23%)
- Depression/anxiety including phobias, panic attacks, and stuttering; increased risk of contemplating suicide (1)
- Impairments of visual perception, sleep disorders, restless leg syndrome, and migraine headaches
- Cardiometabolic disorders, especially obesity, circulatory system diseases, type 2 diabetes (50%) (3)
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