Mark gets second looks from people because he twitches, shrugs, jerks his shoulders, and flexes his jaw. He can stop doing these things, but not for long. But Mark isn't weird. He has a condition called Tourette syndrome. Tourette syndrome is a condition of the central nervous system that causes tics.
Tics are movements or sounds that are repeated over and over.
A person with Tourette syndrome has very little or no control over twitches, movements, or noises that he makes. Tourette syndrome gets its name from a French doctor named George Gilles de la Tourette, who was the first to fully describe the condition back in 1885. It is sometimes also known as Tourette's syndrome, Tourette disorder, or Gilles de la Tourette syndrome. It's believed that as many as 100,000 Americans may have it, but many haven't been diagnosed because it doesn't interfere with their lives. Tourette syndrome is more common in boys than in girls, and it almost always starts before age 21.