Transient tic disorder and the spectrum of Tourette's syndrome

Transient tic disorder (TTD) has not generally been considered part of the spectrum of Tourette's syndrome (TS). We studied a large kindred affected by TS and identified two family members with TTD who are very likely obligate carriers of the TS gene. Our observations indicate that TTD is a possible expression of the TS gene and that individuals with TTD may transmit TS to their offspring.