We studied CNVs in a sample of 210 unrelated TS cases ascertained in two closely related Latin American population isolates and 285 unrelated population controls. The populations of Antioquia, Colombia, and of the Central Valley of Costa Rica (CVCR) have similar and partly shared demographic histories and are genetically closely related [14], [15]. They are therefore expected to show an enrichment for shared predisposing factors for complex genetic conditions, including TS [14]–[17]. Of the cases, 81 were recruited at the Neuropaediatrics Clinic of Hospital Universitario San Vicente de Paúl (Antioquia, Colombia) and 129 were recruited at Hospital Nacional de Niños (San José, Costa Rica). Diagnosis was based on DSM-IV criteria, focusing on narrowly defined moderate to severe TS. The mean age of cases was 13 years, with a mean age for the start of symptoms at 6.4 years. In addition to TS, 48% of the cases have a diagnosis of ADHD and 53% have OCD. An additional set of 53 TS cases used for MLPA-based follow-up (see below) was also recruited through the Neuropaediatrics Clinic of Hospital Universitario San Vicente
