Genetic studies have provided evidence that Tourette Syndrome (TS) is familial, meaning that having one affected family member with TS increases the possibility of having other family members affected as well. These studies have also shown that TS is, in fact, a genetically heterogeneous disorder, and that at least some forms of TS are etiologically related to Obsessive Compulsive Disorder (OCD). That is why it has become increasingly clear that molecular genetics alone may not be able to find and characterize all the genes involved in causing TS. Needed is the establishment of more homogeneous and valid subgroups to identify which clinical characteristics are more likely to be transmitted than others within families. The identification of TS subtypes is important not only because subgroups of patients may require different treatment strategies, but also because knowing these subtypes will allow us to better understand how genetic and environmental factors, involving specific neurobiological substrates, interact in the etiology of TS. Some clinical and phenomenological characteristics show more promise in helping better define these TS phenotypes. These include cases in which tics are associated with obsessive-compulsive symptoms (OCS) and those in which a family history of tics, TS, OCS and/or OCD are present. The main objective of this study is to determine which clinical and phenomenological characteristics occur more frequently in the same families and therefore may contribute to the establishment of more genetically homogeneous subgroups of TS patients. We believe that it is only through the correct identification of inherited clinical characteristics that we will be able to elucidate the genetic factors important in the manifestation of OCD. We hope that our findings may give additional clues for ongoing and future genetic studies. We plan to achieve this goal by interviewing 115 children and adolescents with OCD (probands) and all their first-degree relatives using semi-structured interviews. To date, 100 probands and their 337 first-degree family members have already been interviewed. From these 100 probands, 50 children and/or adolescents were also diagnosed as having tics and/or TS. After the data collection, we plan a review of the data to determine which psychiatric diagnoses were present for each of the participants. For tics, OC symptoms and ADHD, we will not only assign diagnoses, but also ascertain all present symptoms, and their respective ages of onset. We also plan to determine which clinical symptoms tend to co-occur in the families by analyzing all the symptoms reported by the probands and their relatives and the possible correlation among them. We are hopeful that this large sample size will allow us to investigate the relationship between the symptoms and symptom factors presented by the probands and their relatives in a multidimensional way instead of using the more simple dichotomous approach (affected vs. non-affected). Maria C. Rosario-Campos, M.D., M.Sc., Yale Child Study Center, New Haven, CT Award: $34,992 This study is underwritten through a generous contribution by the Tourette Association of Illinois Tourette Association of America Inc. – Research Grant Award 2002-2003
A Family Genetic Study of Children and Adolescents with TS and OCD
Institution Organization Name
Yale Child Study Center
Rosario-Campos, Maria, MD, M.S.