An independent case-control replication sample from Iceland (deCODE genetics, Reykjavik, Iceland) consisted of 706 Icelandic Tourette syndrome cases and 466 cases with other tic disorders (chronic tics or unspecified tic disorder) (Supplemental Methods). 127,164 unscreened population-matched controls were also available; 6,068 of these were screened and reported no lifetime subclinical motor or vocal tics. Cases and controls were genotyped at deCODE on Illumina SNP arrays (Supplemental Methods).
