TS is a childhood onset neuropsychiatric illness characterised by the occurrence of multiple, motor and vocal tics and is often associated with obsessive-compulsive disorder (OCD) and attention-deficit hyperactivity disorder (ADHD) [1]–[5]. Twin studies have estimated a sibling relative risk ratio for TS of about 6–8 [2], one of the highest amongst neuropsychiatric disorders. However, identification of genetic variants underlying TS has proven difficult [5]–[7]. Genome-wide linkage and candidate gene association studies have failed to provide robust evidence implicating specific loci, and a recent GWAS has not identified common variants associated with TS at genome-wide significance thresholds [8]. The observation of chromosomal abnormalities in TS families [9]–[11] has suggested the possibility that genomic rearrangements could play an important role in this disorder, but prior studies have provided conflicting evidence regarding the involvement of copy number variants (CNVs) in TS [12], [13]. To further evaluate the role of CNVs in TS, we performed a genomewide study of CNVs in a case/control sample from two well-studied, closely related Latin American population isolates.
