Overall Abstract Gilles de la Tourette Syndrome (TS) is a common, albeit still under-diagnosed, neuropsychiatric disorder that is caused by a complex genetic basis, interacting with environmental factors. This symposium will showcase exciting findings from all current large-scale collaborative efforts aiming to elucidate the genetic background of TS, through diverse approaches and studies of several thousands of individuals with TS; genome-wide association studies (GWAS) aiming to identify common variants associated to the disorder, whole-exome sequencing approaches seeking rare variants, gene-expression studies aiming to identify the relative contribution of genetics versus environmental factors, and sophisticated approaches aiming to dissect complex and comorbid phenotypes. We will present novel TS susceptibility genes implicated on a genome-wide significance level either by GWAS, large-scale CNV scans or whole-exome sequencing and introduce heritable TS sub-phenotypes. We will also present large-scale GWAS meta-analysis of TS together with other, often comorbid neurodevelopmental disorders, such as obsessive-compulsive disorder, attention deficit hyperactivity disorder and autism. Finally, after more than two decades of active research aiming to identify the genetic background of TS etiology, we are on the verge of a new era, yielding exciting and rapid discoveries in the field of TS genetics. Investigators from around the world, representing multiple disciplines and scientific approaches, are joining their efforts in large-scale initiatives supported both by the European Union and US National funding agencies. Propelled by the gradual availability of large scale TS cohorts, novel methodologies for the study of both common and rare genetic variants, and importantly, sheer enthusiasm by multiple researchers working together across different countries, the new era of TS genetics holds the promise to identify novel targets for improved therapies.