The relationship between Obsessive Compulsive Disorder (OCD) and Tourette Syndrome (TS) and chronic motor tics (CMT). Most of the studies looking for a relationship among these disorders have begun with individuals with TS and asked if their relatives have an increased risk of OCD, and the answer was yes. We will begin with patients being treated for OCD and determine the frequency of TS and CMT in their relatives. If the disorders are related at the causal level then there should be an increased risk in the relatives for any of the three diagnoses. The second aspect of the study will examine the evidence with the families ascertained for OCD being the result of a genetic disorder. We will do segregation analysis to test whether the disorder is inherited as an autosomal dominant disorder as suspected. We can test whether or not the TS and CMT relatives represent different manifestations of the same gene in the families. For large families with multiple cases of OCD, and especially if there are cases of TS, we will store DNA for genetic linkage analyses in the future. The TSA is funding research to map the gene for TS, and as soon as its location is known, we will test immediately to see if the OCD families share the same genetic location. Humberto Nicolini, M.D. U.C.L.A., Los Angeles, CA Award:$20,000 Tourette Association of America Inc. – Research Grant Award 1989