Analysis of CAG repeat expansions in restless legs syndrome

A relatively high prevalence of restless legs syndrome symptoms has been recently reported in a substantial proportion of patients affected with spinocerebellar ataxia type 3. Our aim was to investigate whether there is a common genetic etiology between restless legs syndrome and spinocerebellar ataxia type 3.

Systematic differences in the number of spinocerebellar ataxia type 3 trinucleotide repeat were investigated by means of an association study. The relationship between the size of the expanded alleles and several clinical features was also considered.

125 extensively characterized restless legs syndrome patients compared with 188 healthy controls matched for ethnic background.

N/A.

No CAG repeat expansions in the pathologic or intermediate range were detected in any of the examined subjects, including patients and controls. A similar allelic distribution was observed in both groups (Mann-Whitney U test = 78406; P = 0.99). Moreover, stratification analyses of the patients' samples according to different clinical and polysomnographic variables disclosed no significant differences.

These results do not provide evidence toward an involvement of large CAG trinucleotide expansions at the spinocerebellar ataxia type 3 locus in idiopathic restless legs syndrome.