Identification of Genes Predisposing to TS in the French Canadian Population

Grant Type
Grant Year
Institution Location
Institution Organization Name
University of Montreal Canada
Investigators Name
Rouleau, Guy, MD, PhD

Tourette Syndrome (TS) is a complex psychiatric disorder that usually begins during childhood. The causes of TS are not known, but it has been established that this syndrome is clustered in families and is transmitted from parents to children. Moreover, since TS is unlikely to be caused by a single gene, the disorder falls in the “complex genetic trait” category and it is predicted that many different genes influence disease presentation. Populations that have remained isolated for extended periods of time, such as the people of Quebec, are called population isolates. They offer advantages in the identification of genes involved in complex traits. The goal of this study is to identify genes that predispose individuals in the French- Canadian (FC) population to TS. Initially, we will search for predisposing TS genes in the whole genome (genome-scan) of 96 FC trios (father, mother and affected child) and later in large FC Tourette families. Since TS is a complex disease which is often hard to diagnose, we propose that the identification of genes involved in TS has remained elusive due to “mixed” sampling, meaning that previous investigators performed genetic studies on samples that included individuals not affected by TS or on individuals where TS was caused by different genes. To avoid this problem and to collect the most homogeneous TS population possible, we propose to perform a strict classification of the disease presentation in our group of patients, as well as a classification per region of origin in Quebec. Any cases of TS without a family history of the disorder (sporadic) will be excluded. The identification of one or more regions in the genome predisposing individuals to TS would provide a significant first step in the identification of a TS gene and give an indication of the mode in which TS is transmitted in families. Furthermore, based on population isolates, our approach will demonstrate the value of this type of study in identifying genes involved in complex genetic traits. The identification of a gene implicated in TS would allow us to better understand the syndrome and enable the development of diagnostic tests. It could also be an important step in the development of specific drugs to treat or prevent TS and other psychiatric conditions that sometimes manifest themselves together with TS. Guy A. Rouleau, M.D., Ph.D. University of Montreal, Montreal, Quebec, Canada Award: $65,000 Tourette Association of America Inc. – Research Grant Award 2005-2006