What causes Tourettes disorder?
Tourette’s disorder is an autosomal dominant disorder. Autosomal means that both males and females are affected, and dominant means that one copy of the gene is necessary to have the condition. This means that a parent with TD or a parent who has the gene for TD has a 50/50 chance, with each pregnancy, to pass the gene on. TD is associated with a non-genetic cause in 10 percent to 15 percent of children. Complications of pregnancy, low birth weight, head trauma, carbon monoxide poisoning, and encephalitis are thought to be associated with the onset of non-genetic TD. Dominant disorders exhibit something known as incomplete penetrance, which means that not everyone with the gene will have symptoms of Tourette’s disorder. In other words, if a parent passes the gene on to a child, the child may not have any symptoms of the disorder. If a daughter inherits the gene, there is a 70 percent chance that she will have at least one of the signs of TD. On the other hand, if a son inherits the gen
