Journal of Neurology, Neurosurgery, and Psychiatry 1983;46:75-77 Short report Gilles de la Tourette's syndrome in monozygotic twins

SUMMARY Concordance is reported of Gilles de la Tourette syndrome in a male twin pair in whom phenotyping revealed a>98-7 % probability that they were monozygotic. The development and extent of the illness differed markedly in the two subjects. Our findings are compatible with the view that there is a genetic form of Gilles de la Tourette syndrome. Gilles de la bTourette's syndrome is a condition of unknown aetiology which is characterised by motor and vocal tics developing in childhood.1 Coprolalia is the most distinctive feature and occurs in approximately 50 % of subjects.2 Both environmentally linked and hereditary forms are believed to occur ' though some authors have questioned the significance of genetic factors.3 Few reports are available on Gilles de la Tourette syndrome in twins.1 2 4-6 We report on the concordance of the syndrome in a monozygotic twin pair in whom the development and progress of the disorder differed markedly in the two subjects. Clinical data and methods The patients were male, of non-Jewish background, who were reared together. Collateral information was obtained from the parents. Obstetric records were personally examined. The mother was a full term primagravida. Pregnancy was unremarkable. The placenta was single and monochorionic. The twins were identical for the following blood group antigens