Official websites use. Share sensitive information only on official, secure websites. Correspondence to: Dr. David L. Family, twin and segregation studies provide strong evidence for the genetic nature of GTS. GTS is a heterogeneous disorder with complex inheritance patterns and phenotypic manifestations. The largest genome wide linkage study to date observed evidence for linkage on chromosome 2p No causative candidate genes have been identified, and recent studies suggest that the newly identified candidate gene SLITRK1 is not a major risk gene for the majority of individuals with GTS.
The genetics of GTS are complex and not well understood. However, large-scale collaborations are needed to provide enough power to utilize the GWAS design for discovery of causative mutations. Knowledge of susceptibility mutations and biological pathways involved should eventually lead to new treatment paradigms for GTS. In the original description of the syndrome that bears his name, Georges Gilles de la Tourette observed that the disorder was familial [ 1 ].
Subsequently, there has been considerable research devoted to systematically examining whether that original observation could be replicated and whether the observed familiality is due in part to genetic factors. These studies have included family studies, twin studies, genetic linkage studies and genetic association candidate gene studies.
Nevertheless, results from these studies provide an important first step for determining whether genetic factors are important in the manifestation of the condition. Results from GTS family studies consistently show a 10 to fold increase in the rates of GTS in first-degree relatives when compared to those rates in the general population [ 3 β 12 ] making it one of the most heritable childhood onset neuropsychiatric conditions [ 13 ].
These rates are significantly greater than those in the general population e. Understanding the etiology of comorbid GTS conditions is especially critical, as children with comorbid diagnoses exhibit greater psychopathological burden [ 21 ], have more severe tic symptoms [ 15 ], and are at higher risk for aggressive behaviors and frequent anger outbursts [ 14 , 22 , 23 ]. In addition to demonstrating that GTS is familial, the family study design can be utilized to examine the familial relationship between GTS and its comorbid disorders.
