Clinical characteristics of ataxia-telangiectasia presenting dystonia as a main manifestation

Introduction: Besides cerebellar ataxia, various other movement disorders, including dystonia, could manifest as main clinical symptoms in ataxia-telangiectasia (A-T). However, the clinical characteristics of dystonic A-T patients are not clearly elucidated. Methods: To investigate the characteristics of dystonic A-T, we screened previous reports with A-T patients presenting dystonia as a main manifestation, and included 38 dystonic A-T patients from 16 previous studies and our 2 cases. We reviewed clinical and demographic data of dystonic A-T patients. Additionally, to figure out clinical meaning of cerebellar involvement in dystonic A-T, we divided them into two groups based on the presence of cerebellar involvement, and compared clinical features between two groups. Results: In the patients with dystonic A-T, dystonia tended to appear during childhood or adolescence and became generalized over time. Choreoathetosis and myoclonus accompanied more frequently than the typical clinical features, including cerebellar ataxia or atrophy, telangiectasia, or oculomotor apraxia. Additionally, alpha-fetoprotein level was also elevated in the patients with dystonic A-T. When we compared dystonic A-T with and without cerebellar involvement, the former was related with more chance for telangiectasia and oculomotor apraxia, while the latter with that for choreoathetosis and malignancy. Conclusion: Even without ataxia, telangiectasia, or oculomotor apraxia, A-T should be considered in undiagnosed dystonia, especially generalized dystonia which started from childhood or adolescence period, and alpha-fetoprotein level can be a useful screening tool. In addition, cerebellar involvement is important considering different phenotype in dystonic A-T patients with and without cerebellar sign.