[Risk factors for Tourette syndrome].

Objective: To identify the risk factors for Tourette syndrome (TS) in children.

Methods: Through a genetic epidemiologic case control study, segregation ratio was estimated using the method of Li-Manted-Gart in 80 children with TS. Heritability for the first- and second-degree relatives was estimated using the Falconer regression method. In addition, the 80 children and 80 controls with other diseases were evaluated using the Family Environment Scale and a self-designed questionnaire. Risk factors for TS were investigated using single factor and multifactor regression analysis.

Results: The segregation ratio of TS was 0.1176. Heritabilities for the first- and second-degree relatives were (49.7±2.6)% and (21.5±3.4)% respectively. The weighted mean heritability of the first-degree and second-degree relatives was (39.5±2.1)%. Significantly decreased scores were noted in independence, active-recreational orientation and organization and increased scores were noted in the conflict and control in the TS group compared with the control group (P<0.01). Single factor analysis indicated that the risk factors for TS included family history, type of home education, maternal smoking, family conflict, low level of parental education, family control and fetal anoxia. Multifactor regression analysis indicated that there were five important risk factors for TS: family history, family conflict, type of family education, low level of parental education and maternal smoking.

Conclusions: Both heredity and environment are involved in the pathogenesis of TS. The mode of inheritance for TS is polygenic. Improving the living environments of children with a family history of TS is of prime importance.