TOURETTE'S SYNDROME

Tourette''s Syndrome

Tourette''s Syndrome

Tourette's syndrome (TS) is a neurobehavioral disorder named after the French neurologist Georges Gilles de la Tourette who in 1885 described nine patients with TS symptoms including verbal and motor childhood-onset tics and other behavioral problems including poor impulse control and obsessivecompulsive behaviors. The disease, once believed to be extremely rare, is now considered to be quite common, affecting approximately 2% percent of the population. The disease afflicts males 5 times more often than females. The onset of TS, as characterized by the emergence of motor and vocal tics, typically emerges between the ages of 3 and 8 with a reduction in these symptoms occurring by age 20.

SYMPTOMS

The hallmarks of TS are the motor and verbal tics. These tics vary in complexity, duration (ranging from 1 year to lifelong), intensity (from mild to severe), and frequency (from rare to constant). Tics are brief movements or sounds that appear unpredictably. They emerge individually or in choreographed clusters and can be expressed either intermittently or continuously for hours. These tics fall into one of several categories: (1) motor tics which can include intense eye blinking, throat clearing, and neck and arm twitching; (2) phonic tics such as repeated utterance of a particular word, shouting (obscenities), or grunting; (3) aggressive phenomenon such as self-injury, hitting, kicking, or biting self or others; and (4) compulsive behaviors that may include hand-washing, door locking, checking and organizing objects, and touching or tapping others and objects.

The motor and phonic symptoms typically wax and wane. This waxing and waning is most likely influenced by ongoing brain developmental changes and environmental influences such as stress. Additionally, medications for TS can also cause changes in the brain that result in corresponding behavioral changes. The repertoire and severity of symptoms of TS patients, therefore, require constant monitoring by the patient and family, as well as by the physician who will adjust the dose and type of medication accordingly. Studies have reported that the highest incidence and severity of tics occur with anticipation or resolution of emotional changes. Consistent with this, stress, anxiety, and fatigue exacerbate tics, and ironically, the very urge and attempt to control the tic can itself lead to additional stress and anxiety. Altogether, the disease and its consequences can often lead to problems in school performance and self-esteem, and also in a variety of social and behavioral problems at school, at home, and in society in general.

GENETICS

Tourette's syndrome has a significant genetic component. Several genes have been identified through family studies, segregation analyses, candidate gene studies, and linkage studies. TS inheritance may involve several mechanisms including autosomal dominant, bilinear, or polygenic mechanisms. Candidate genes for TS pose a genetic susceptibility with such factors as preor postnatal stress, and other environmental factors such as viral infections or stress, increasing their likelihood of expression. It is critical therefore to continue studies designed to identify specific gene-environmental interactions. The candidate genes identified thus far appear to be involved in the regulation of brain development and neurochemical ...