Severity of Tourette's syndrome in one large kindred. Implication for determination of disease prevalence rate
R. Kurlan, J. Behr, L. Medved, I. Shoulson, D. Pauls and K. K. Kidd
An accurate prevalence rate for Tourette's syndrome (TS) has not been
established. To assess severity of illness, a potential source of bias in
determining prevalence rate, we administered standardized questionnaires
and examinations to 159 members of a large Mennonite kindred showing
apparent autosomal dominant transmission of motor and vocal tics (TS) or
chronic motor tics (CMTs). Fifty-four family members were diagnosed as
having definite or probable TS or CMTs. For these 54 subjects, 30% (n = 16)
were unaware of tics noted by the examiners and only 18.5% (n = 10) had
sought medical care. Our findings suggest that most cases of TS and CMTs
are mild and do not come to medical attention. These tic disorders are
probably much more prevalent than generally appreciated.
