However, that genetic predisposition may express itself as TS, as a milder tic disorder or as obsessive compulsive symptoms with no tics at all. It is known that a higher than normal incidence of milder tic disorders and obsessive compulsive behaviors occur in the families of TS patients. The sex of the offspring also influences the expression of the gene. The chance that the gene-carrying child of a person with TS will have symptoms is at least three to four times higher for a son than for a daughter. The cause in these instances is unknown.
Many people experience marked improvement in their late teens or early twenties.
Most people with TS get better, not worse, as they mature, and those diagnosed with TS have a normal life span. Since many people with TS have yet to be diagnosed, there are no absolute figures. In 1825 the first case of TS was reported in medical literature with a description of the Marquise de Dampierre, a noblewoman whose symptoms included involuntary tics of many parts of her body and various vocalizations including coprolalia and echolalia. Later, Dr. Georges Gilles de la Tourette, the French neurologist for whom the disorder is named, first described nine cases in 1885. That focus has been enhanced by the efforts of a TSA- supported international group of scientists who have formed a unique network to share what they know about the genetics of TS and to systematically cooperate to unravel the unknown.