SLC6A3 and Tourette syndrome: The Tourette Syndrome Association International Consortium for Genetics (TSAICG) and others investigated various susceptibility genes in the dopaminergic, serotonergic and glutamatergic pathways, such as the receptors and transporters DRD2, DAT1 (SLC6A3), HTR2A, and EAAT1 but later switched to GWAS and CNV studies (16).