Tourette syndrome is a condition where the sufferer has compulsive tics. These may be behavioural or physical, and are believed to have an overwhelmingly genetic cause. You either get the genes that cause it or you don't. Tics and other symptoms are usually much worse before adulthood and many people may never be diagnosed if their symptoms are mild enough.
BUT, the thing about genes, is that sometimes environmental influences switch them on (or not, in effect). So you may inherit the genes, but if you never encounter certain environmental triggers, the genes may never manifest (cause symptoms).
It is known that women who smoke while pregnant are much more likely to have babies with Tourette's (and related problems, including obsessive-compulsive disorder and Attention Deficit and Hyperactivity Disorder). So certain aspects of the womb environment can be a trigger and therefore, in a sense, "cause" of the condition.
By definition Tourette Syndrome has onset before the age of 18. The exact genes involved haven't been identified, but most people who seem like they ought to get it (close family connections) don't get it, or don't get it severely -- which implies that they aren't encountering enough of the relevant environmental triggers, in spite of genetic susceptibility.
BUT, the thing about genes, is that sometimes environmental influences switch them on (or not, in effect). So you may inherit the genes, but if you never encounter certain environmental triggers, the genes may never manifest (cause symptoms).
It is known that women who smoke while pregnant are much more likely to have babies with Tourette's (and related problems, including obsessive-compulsive disorder and Attention Deficit and Hyperactivity Disorder). So certain aspects of the womb environment can be a trigger and therefore, in a sense, "cause" of the condition.
By definition Tourette Syndrome has onset before the age of 18. The exact genes involved haven't been identified, but most people who seem like they ought to get it (close family connections) don't get it, or don't get it severely -- which implies that they aren't encountering enough of the relevant environmental triggers, in spite of genetic susceptibility.
