A controlled family history study of Tourette's syndrome, I: Attention-deficit hyperactivity disorder and learning disorders.
Gilles de la Tourette's syndrome (TS) is a common, hereditary neuropsychiatric disorder. While its diagnostic feature is the presence of suppressible motor and vocal tics, a wide range of impulsive, compulsive, attentional, learning, mood, and anxiety disorders are also present in many patients. To determine if attentional and learning problems are part of the expression of the Gts gene (or genes), the authors analyzed family histories of 130 TS probands with 1851 relatives and 25 control probands with 541 relatives--a total of 2392 relatives. The frequency of attention-deficit hyperactivity disorder (ADHD) or learning disorders was significantly increased in the relatives of the TS probands. The data on first-degree relatives suggest that when the Gts gene is expressed in this form, in two thirds of the cases tics are also present and in one third they are not. These observations are consistent with the proposal that ADHD and learning disorders form an integral part of the expression of the Gts gene or genes.