LAUSR

Reporting on behalf of the European Multicenter Tics (EMTICS) in Children Study, Dr. Schrag et al. prospectively followed up asymptomatic children 3–10 years of age with a first-degree relative diagnosed with a chronic tic disorder. One quarter (23.6%) of the 259-patient cohort ultimately developed tics; however, there was no relationship between group A streptococcus (GAS) exposure and tic onset. One particular strength of this study is the inclusion of 4 working definitions of GAS exposure based on oropharyngeal or serologic findings; yet no association was found between GAS and tics. Dr. Gupta et al. appropriately recognize the selection bias in this study, which restricted inclusion to participants with a genetic predisposition to a tic disorder. Furthermore, Gupta et al. emphasize the failure to consider a relationship between GAS and a new-onset tic or other movement disorder may result in the withholding of appropriate antibiotics, which may improve such symptoms. The EMTICS investigators confirm that while their negative results (and others) may be generalizable to many patients with a tic disorder, they are unable to comment on the relationship between GAS and a sporadic tic condition.