Restless legs syndrome in spinocerebellar ataxia types 1, 2, and 3

To identify the prevalence and determinants of restless legs syndrome (RLS) in spinocerebellar ataxia (SCA) we studied 58 patients with a molecular di agnosis of SCA1, SCA2 and SCA3. Data on the symptoms of RLS were collected by a standardized questionnaire, and RLS was diagnosed when patients met th e four minimal criteria of the syndrome as recently defined by an internati onal study group. In addition, we studied the relationship between RLS and age, age at ataxia onset, CAG repeat length, and nerve conduction and evoke d potentials data. RLS was significantly more frequent in SCA patients than in controls (28% vs. 10%). Age at RLS onset in SCA was 49.0 +/- 10.9 years . There were no significant differences in nerve conduction or evoked poten tials between RLS and non-RLS SCA patients. The probability of developing R LS increased with age but not with CAG repeat length or higher age of ataxi a onset. The data provide evidence that patients with SCAI, SCA2 and SCA3 a re per se more susceptible to RLS than non-affected individuals. The probab ility of developing RLS is related principally to the period over which the CAG repeat mutation exerts its effect and not to CAG repeat length or age of ataxia onset.