Tics are sudden, non-rhythmic stereotyped movements or vocalizations, such as blinking, sniffing, tapping or saying words. Transient tics are very common, and even chronic tics affect one in 30 people. Tourette Syndrome (TS) is diagnosed clinically based on chronic motor and vocal tics beginning before adulthood without another cause. TS is highly heritable though not yet convincingly associated with a specific gene. Many patients need no specific treatment, but certain medications and behavioral therapies have proven efficacy.