Meta-analysis Confirms That Tourette's Syndrome Is a Polygenic Disorder
In This Article
- In a meta-analysis of multiple studies into the genetics of Tourette's syndrome (TS), investigators found that results from variants in hundreds of genes that work together and having more associated variants results in a more severe form
- They conducted a large-scale genome-wide association study (GWAS) to better understand which risk genes contribute to the development of TS
- Though the meta-analysis revealed multiple gene variants, only one of them was significant for increased TS risk across the entire genome
- The investigators believe that variants that contribute to TS are present in a large portion of the population. While having more variants means a more severe form of TS, the presence of the variants does not mean an individual will have a tic disorder
Researchers understand that Tourette's syndrome (TS) is a genetic disorder, but only a few risk-associated gene variants have been identified. Therefore, they needed large-scale genome-wide association studies (GWAS) to better understand which risk genes contribute to the development of TS.
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An international team, led by researchers at Massachusetts General Hospital including Jeremiah Scharf, MD, PhD, director of the Tics Disorder Unit and Division of Movement Disorders, along with collaborators at UCLA, the University of Florida and Purdue University, conducted a meta-analysis of multiple studies into the genetics of TS. In The American Journal of Psychiatry, they report that Tourette's results from variants in hundreds of genes working together and having TS-associated variants can lead to a more severe form of TS.
Through meta-analysis, the investigators combined the results from the only published GWAS study with recent data from the Tourette Association of America International Consortium for Genetics, the Gilles de la Tourette GWAS Replication Initiative and the Tourette International Collaborative Genetics Study. The study included a total of 4,819 people with TS and 9,500 controls. They also conducted a secondary analysis of the Iceland-based deCode genetics study to compare 700 people with TS to over 450 people with other tic disorders and over 6,000 controls.
Though the meta-analysis revealed multiple gene variants, only one of them was significant for increased TS risk across the entire genome. A polygenic risk score showed that inheriting more TS variants increases the symptoms of TS. However, having the variants for TS does not mean that an individual will have a tic disorder.
Developing a polygenic risk score for TS may mean that there is possibility of predicting whether the symptoms of children with tics will worsen or lessen over time. The next step would be to expand the study to an even larger sample of individuals to better clarify the genetic mechanisms of TS.
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