The child with Tourette's Disorder (TD) has involuntary motor and vocal tics that can vary and wax and wane with time. (A tic is a rapid, repeated twitch that produces a quick, sudden movement. A vocal tic is a sound made involuntarily.) Tics may involve different parts of the body; the most common motor tics are blinking, shrugging, grimacing and nose-twitching. Vocal tics may include meaningless sounds and noises, including grunting, tongue-clicking, hooting and throat-clearing. TD is thought to be due to genetic factors and faulty brain chemistry. Treatment includes genetic counseling, psychoeducation, and pharmacotherapy.