Last year, we identified a large Men­nonite family in which features of Tourette Syndrome are inherited in an autosomal dominant pattern. We that the family included 8 to 10 affected in­dividuals, making it particularly well-suited for application of family linkage analysis. “Genetic linkage” can be defined as the location of the two genes so close together on the same chromosome that they are in­herited together. Recombinant DNA technology provides a method for identify­ing heritable DNA markers which can be used to follow the inheritance of a given segment of DNA through several genera­tions of a particular family to assess the consistency of segregation with a disease gene. Such family linkage studies have recently made it possible to locate the genes for Huntington’s disease and other inherited illnesses. In August, 1984, funded by the Tourette Syndrome Association, we traveled to a small farming community in northern Alberta, Canada to investigate this family. We have now ascertained more than 500 members of the kindred and have confirm­ed that tics affect more than 50 individuals in 5 generations. We administered a stand­ardized questionnaire concerning symp­toms of Tourette Syndrome to all available family members and videotaped those reporting or observed to have tics. Blood samples were collected from 69 family members for establishment of white blood cell lines as a permanent source of DNA to be used in linkage analysis. Our current research project extends these studies. We plan to interview and sample blood from more than 100 addi­tional family members. In addition, we will similarly investigate a second large family with Tourette Syndrome located in Michigan. Evaluation of the additional members of the Canadian pedigree and also of the second pedigree should greatly enhance the chances of family linkage analysis to establish linkage between the disease gene and genetic markers. Localiza­tion of the gene for Tourette Syndrome would have a major impact on the diagnosis, treatment and understanding of this disorder. Roger Kurlan, M.D. Assistant Professor of Neurology The University of Rochester Medical Center, Rochester, NY Award: $15,000 Tourette Association of America, Inc. – Research Grant Award 1985