Inheritance of TS
In families with a member who has TS, tic disorders and obsessive-compulsive behaviours are typically more common. There are some cases of TS with no known family history. It is now believed that tic disorders are not the result of one major gene, but rather several genes which can be influenced by environmental and other factors. For reasons not fully understood, the chance that a male child will have a tic disorder is roughly 4 times that of a female child.