A nonconsanguineous two-generation pedigree was referred to our laboratory (Fig. 1). The father and all eight offspring met the criteria for Tourette's syndrome in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (Table S1 in the Supplementary Appendix). Two children and the father also have obsessive–compulsive disorder. The mother, her parents, and her extended family are reportedly free from Tourette's syndrome, chronic tics, and obsessive–compulsive disorder.
