Analysis of the pedigrees of 250 cases of Tourette Syndrome has demonstrated the involvement of a single major gene responsible for the Tourette Syndrome-chronic multiple tic disorder. The isolation and cloning of this Tourette Syndrome gene would represent an enormous advance leading to improved diagnosis and a better understanding of the variability and basic cause of Tourette Syndrome. However, the immediate product of the TS gene Is completely unknown. To attempt to identify this gene a new technique allowing quantitation of individual messenger RNAs of normal and Tourette Syndrome tissues will be used. If the mutation is a deletion or a mutation which increases or decreases the amount of messenger RNA produced by the Tourette Syndrome gene, this technique is capable of detecting this alteration. Identification of the TS messenger RNA would allow the identification and cloning of the TS gene. David E. Comings, M.D. Director, Department of Medical Genetics City of Hope Medical Center, Duarte, CA Award: $15,000 Tourette Association of America, Inc. – Research Grant Award 1984