Recent research suggests that a small number of Tourette syndrome cases may be caused by a defect on chromosome 13 of gene SLITRK1. Some cases of tourettism (tics due to reasons other than inherited Tourette's syndrome) can be caused by mutation.[10] The finding of a chromosomal abnormality appears to apply to a very small minority of cases (1–2%). Studies to locate all of the genes implicated in Tourette's syndrome are ongoing.[13]